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PRACTICAL 
IRON  FOUNDING 


BY 


JOSEPH   G.    HORNER,   A.M.I.MECH.E, 

AUTHOR  OF  "PRINCIPLES  OF  PATTERN  MAKING,"  "  METAL  TURNING," 
"PRINCIPLES  OF  FITTING,"  ETC. 


With  Two  Hundred  and  Eighty-Three  Illustrations 


FOURTH  EDITION,  THOROUGHLY  REVISED 
AND  ENLARGED 


NEW  YOKE 

D.  VAN  NOSTEAND  COMPANY 

25,  PARK  PLACE 

LONDON:    WHITTAKER  AND  CO. 

1914 


CHISWICK  PRESS  :  CHARLES  WHlTlflNGHAM  AND  CO. 
TOOKS  COURT,  CHANCERY  LANE,  LONDON. 


PREFACE  TO  FIRST  EDITION 

THIS  is  an  attempt  to  give  a  condensed  account  of 
the  principles  and  practice  of  Iron  Founding.  It  is 
written  both  for  the  student  and  for  the  practical 
man.  I  have  stated  and  explained  principles,  and 
have  also  included  the  most  recent  practice,  particu- 
larly as  it  relates  to  the  two  branches  of  machine 
moulding  and  the  melting  of  iron. 

JOSEPH  HORNER. 


PREFACE  TO  FOUKTH  EDITION 

SINCE  this  volume  was  written  great  changes  have 
been  accomplished  in  the  Iron  Foundry.  This  is 
the  explanation  of  the  fact  that  the  amount  of 
matter  in  the  present  edition  is  just  double  that  of 
the  previous  one,  and  that  certain  portions,  notably 
that  of  machine  moulding,  have  been  wholly  re- 
written . 

Additional  examples  of  moulds  have  been  intro- 
duced, and  some  new  chapters  prepared.  It  is  now 
more  than  an  elementary  treatise,  and  should  pos- 
sess a  correspondingly  higher  value  than  the  pre- 
vious editions. 

BATH,  1914 


VI 


CONTENTS 

CHAPTER  PAGE 

I.  PRINCIPLES    .                  1 

II.  SANDS  AND  THEIR  PREPARATION       ...  4 

III.  IRON — MELTING  AND  TESTING         ...  28 

IV.  CUPOLAS,  BLAST,  AND  LADLES          ...  47 
V.  THE  SHOPS,  AND  THEIR  EQUIPMENT          .         .  71 

VI.  MOULDING  BOXES  AND  TOOLS  .         .         .93 

VII.  SHRINKAGE — CURVING — FRACTURES — FAULTS  .  113 

VIII.  PRINCIPLES  OF  GREEN  SAND  MOULDING  .         .  137 

IX.  EXAMPLES  OF  GREEN  SAND  MOULDING     .         .  163 

X.  DRY  SAND  MOULDING 185 

XL  CORES .  215 

XII.  LOAM  WORK 234 

XIII.  THE  ELEMENTS  OF  MACHINE  MOULDING  .         .  263 

XIV.  EXAMPLES  OF  MOULDING  MACHINES         .         .  279 
XV.  MACHINE  MOULDED  GEARS      ....  329 

XVI.  MISCELLANEOUS     ECONOMIES  —  WEIGHTS     OF 

CASTINGS 347 

APPENDIX  : 

Tables  I.  Sand  Mixtures      .         .         .  •       .         .  385 

II,  III.  Particulars,  "  Bapid  "  Cupolas     .         .  389 

IV.  Particulars,  Boot's  Blowers          .         .  392 

V.  Sturtevant  Fans 393 

VI.  .Crane  Chains 394 

VII.  Bopes,  various 394 

VIII.  Composition  of  Pig  Iron       .         .         .395 

IX.  Mensuration 396 

vii 


viii  CONTENTS 

PAGE 

APPENDIX — continued 

Tables  X.  Weights  of  Various  Metals  .  .  .399 

XI.  Weights  of  Cast  Iron  Cylinders  .  .     400 

XII.  Comparative  Weights           .  .  .     402 

XIII.  Weights,  Cast  Iron  Balls     .  .  .403 

XIV.  Decimal  Equivalents   ....     404 
XV.  Decimal  Approximations      .  .  .     404 

INDEX       .  405 


PRACTICAL  IRON  FOUNDING 

CHAPTER  I 

PRINCIPLES 

IN  this  text-book  the  endeavour  will  be  to  explain  and 
illustrate  in  a  clear  and  concise  manner  the  principles 
and  practice  of  iron  moulding  and  founding.  Though  a 
dirty  trade,  more  of  technical  skill  and  forethought  are 
required,  more  difficulties  have  to  be  encountered  than  in 
many  trades  of  more  apparent  importance.  And  as  it 
is  one  the  practice  of  which  is  very  varied  and  extensive, 
and  as  a  thoroughly  exhaustive  treatment  would  occupy 
a  much  larger  treatise  than  this,  judicious  condensation 
will  be  necessary.  But  if  we  endeavour  to  go  down  at 
once  to  first  principles,  and  gain  clear  ideas  as  to  the 
fundamentals  involved  in  iron-moulding,  we  shall  be  able 
to  obtain  such  a  broad  grasp  of  the  subject  as  will  assist 
subsequently  in  the  comprehension  of  details. 

The  matrices  into  which  iron  is  poured  in  order  to 
obtain  castings  of  definite  outlines  are  invariably  either 
of  sand  or  iron.  The  process  in  which  the  latter  is  used 
is  a  small  and  comparatively  restricted  'section,  known 
as  chilling',  the  former  embraces  all  the  ordinary  iron 
castings — those  the  surfaces  of  which  are  not  required  of 
a  hard  and  steely  character.  Recently,  however,  the  prac- 
tice has  been  developing  of  casting  pipes,  wheels,  sash 
weights,  etc.,  in  permanent  moulds  of  iron. 

Sand  is  eminently  adapted  for  casting  metals  into. 
No  material  can  take  its  place,  because  there  is  none 

B 


2  PRA  GTICAL  IRON  FO  UN  DING 

which  is  at  the  same  time  plastic,  porous  and  firm, 
adhesive  and  refractory.  Plasticity  is  necessary  in  order 
that  the  matrix  may  be  moulded  into  any  form,  intricate 
or  otherwise.  Porosity  is  essential  to  permit  of  the  escape 
from  the  moulds  of  the  air  and  of  the  gases  generated  by 
the  act  of  casting,  and  firmness  and  adhesiveness  are  re- 
quired to  withstand  the  liquid  pressure  of  the  molten 
metal.  A  matrix  must  also  be  refractory,  that  is,  able  to 
resist  the  disintegrating  influence  of  great  heat,  and  the 
chemical  action  of  the  hot  iron  itself.  It  must,  moreover, 
be  cheap,  readily  available,  and  not  difficult  to  manipu- 
late. All  these  qualities  are  possessed  by  certain  sands, 
and  mixtures  of  sands,  and  by  no  other  materials. 

The  leading  branches  of  moulding  derive  their  names 
from  the  different  kinds  of  sand  mixtures  used,  termed 
respectively  green  sand,  dry  sand,  loam,  to  be  explained 
directly.  It  will  suffice  just  now  to  remark  that  the  fact 
that  sands  differ  widely  in  their  physical  qualities  is 
apparent  to  any  observant  person,  so  that  while  one  kind 
will  be  loose,  open,  friable,  and  free,  another  will  appear 
as  though  clayey,  greasy,  close,  and  dense.  Advantage 
is  taken  of  these  differences  in  quality  to  obtain  mixtures 
suitable  for  every  class  of  moulded  work,  from  the  thin- 
nest, lightest  rain-water  pipes  to  the  most  massive  and 
heaviest  engine  cylinders  and  bedplates.  Almost  in- 
variably, therefore,  foundry  sand  consists  of  mixtures 
of  various  separate  kinds.  By  judicious  mixture,  grades 
of  any  required  character  can  be  obtained. 

To  enable  the  sand  to  take  the  requisite  definite  im- 
pressions and  outlines,  it  is  necessary  to  employ  patterns, 
the  shapes  of  which  are  in  the  main  the  counterparts  of 
those  of  the  castings  wanted.  These  patterns  are  in  some 
cases  absolutely  like  their  castings,  but  in  others  they 


PRINCIPLES  3 

resemble  them  only  to  a  certain  extent.  Thus,  if  work  is 
to  be  hollow,  the  hollow  portions,  instead  of  being  pro- 
vided in  the  patterns,  may  be  often  much  better  formed 
in  cores-. — prints  on  the  patterns  indicating  their  posi- 
tions, and  the  print  impressions  affording  them  support. 
But  in  much  large  work,  again,  the  patterns  are  mere 
skeletons,  profile  forms,  and  the  mould  is  prepared 
mainly  by  a  process  of  "  sweeping  "  or  "  strickling  "  up. 

In  order  to  effect  delivery  of  patterns,  a  process  of 
loosening  by  rapping  has  to  be  resorted  to,  and  this, 
together  with  the  lifting  or  withdrawal,  tends  to  damage 
the  mould.  To  prevent  or  to  minimize  this  injury,  taper 
is  given  to  patterns,  that  is,  their  dimensions  are  slightly 
diminished  in  their  lower  portions,  or  in  those  which  are 
last  withdrawn  from  the  mould. 

As  iron  shrinks  during  the  process  of  cooling,  an  allow- 
ance has  to  be  given  for  this  "contraction,"  by  making 
the  pattern  and  mould  larger  by  a  corresponding  amount 
than  the  casting  is  required  to  be.  Moreover,  the  forms 
of  some  castings  are  such  that  they  curve  in  cooling,  and 
for  this  also  provision  has  properly  to  be  made  in  their 
patterns. 

Iron  when  molten  behaves  similarly  to  a  liquid  in  all 
respects;  hence  the  conditions  of  liquid  pressure  exist  in 
all  moulds.  The  iron,  therefore,  has  to  be  confined  at 
the  time  of  pouring  by  the  resistance  of  large  bodies  of 
sand  enclosed  in  boxes  or  flasks,  which  are  weighted,  or 
otherwise  secured.  Sufficient  area  of  entry  for  the  metal 
has  to  be  provided  by  means  of  suitable  gates  and  run- 
ners. The  shrinkage  of  metal  in  mass  must  receive 
adequate  compensation  by  feeder  heads.  Owing  to  the 
irregular  outlines  of  cast  work,  flasks  must  be  jointed,  and 
joints  of  various  kinds  have  to  be  made  in  the  mould  itself. 


CHAPTER  II 

SANDS,  AND  THEIR  PREPARATION 

ALTHOUGH  as  stated,  sand  is  not  the  only  material  used 
for  moulds,  yet  ninety-nine  one-hundredths  of  the  moulds 
made  are  prepared  in  sand  in  some  way  or  another,  and 
cast  into  either  moist  or  dried.  Consisting,  as  this  material 
does,  of  a  vast  number  of  distinct  particles,  it  can  readily 
be  compelled  by  ramming  or  pressure  to  take  any  re- 
quired outlines  and  the  finest  impressions  of  the  pattern. 
Though  friable  and  destitute  of  cohesion  in  its  natural  dry 
condition,  it  is  plastic  and  coherent  when  moistened  with 
water;  so  that  when  in  this  state  it  is  capable  not  only 
of  receiving  but  of  retaining  the  impressions  made  by  the 
pattern  after  its  withdrawal.  Further,  the  porosity  of  the 
sand  much  assists  the  free  escape  of  the  gases  generated 
by  casting,  and  which,  in  the  absence  of  a  free  vent, 
would  honeycomb  the  castings  with  innumerable  blow- 
holes. 

But  it  is  obvious  that  sands  are  not  all  alike,  and  a 
very  superficial  knowledge  of  moulding  is  sufficient  to 
show  that  different  classes  of  moulds  must  require  differ- 
ent kinds  of  mixtures  of  sands.  In  their  judicious  choice 
and  proper  mixture  lies  very  much  of  the  moulder's  art; 
so  that  a  foreman  moulder  will  spend  several  months,  or 
even  years,  in  studying  and  experimenting  in  various 
mixtures  before  he  gets  the  very  best  possible  results  in 
his  shop. 

4 


SANDS,  AND  THEIR  PREPARATION  5 

Choice  of  sands. — Primarily  the  choice  depends  very 
much  upon  localities.  When  building  a  new  foundry  one 
would  not  go  to  the  opposite  end  of  England  to  get  sand 
to  lay  down  his  floor,  which  will  properly  be  from  2  ft.  to 
3ft.  or  4  ft.  in  depth.  He  would  purchase  cheap  sand  in  his 
immediate  neighbourhood,  and  there  are  few  localities  in 
which  the  new  red  sandstone,  the  green  sand,  and  chalk 
formations,  or  the  coal  measures,  do  not  furnish  suitable 
material  for  the  moulder.  But  there  are  several  localities 
which  are  famous  for  some  special  qualities  possessed  by 
their  sands  which  render  them  more  suitable  for  some 
classes  of  work  than  for  others,  and  small  quantities  of 
these  sands  are  often  purchased  at  considerable  expense, 
due  chiefly  to  the  cost  of  transit,  for  special  work.  Thus, 
though  the  yellow  and  greenish-yellow  sands  usually 
form  the  basis  of  the  foundry  floor,  the  fine  red  sands 
are  chiefly  employed  for  facing  and  for  fine  moulding. 

The  names  and  qualities  of  some  of  the  best-known 
sands  used  in  this  country  are  summarized  below: 

Erith  sand,  or  London  sand,  is  largely  used  for  green, 
and  loam  moulds.  It  is  suitable  for  light  work,  for 
ordinary  and  moderately  heavy  castings,  and,  mixed  with 
old  loam  and  cow  hair,  for  loam  work.  Devizes  and  Seend 
sands,  used  in  the  West  of  England,  are  of  a  yellow  or 
greenish-yellow  colour,  and  are  used  for  general  and 
heavy  work.  They  are  not  suitable  for  the  finest  work, 
being  coarse  and  close.  Worcester  is  a  fine  red  sand,  used 
for  fine  moulds  and  for  facing  moulds,  in  which  a  coarser 
sand  is  used  for  filling.  Falkirk  sand  is  coarse  and  open, 
and  is  suitable,  therefore,  for  casting  hollow  ware  into, 
its  porosity  allowing  free  vent  for  the  gases.  Belfast  sand 
is  fine ;  it  is  used  for  general  work,  is  mixed  with  rock 
sand,  and  affords  excellent  facing.  Doncaster  sand  is 


6  PRACTICAL  IRON  FOUNDING 

suitable  for  jobbing  work.  It  is  of  a  red  colour,  and 
moderately  open.  Winmoor  sand  is  very  open,  and  used 
for  strong  moulds.  Kippax,  a  yellow  sand,  is  employed 
for  cores,  and  for  dry-sand  moulds.  Mansfield  sand  is 
close,  and  suitable  for  fine  work.  Derbyshire,  Snaitb, 
Shropshire,  Cheshire,  the  Birmingham  district,  and  many 
others,  produce  good  sands  of  various  qualities.  Sea  sand 
is  sometimes  used  for  cores,  and  rock  sand — i.e.,  rotten 
rock — is  employed  for  imparting  strength  to  weaker 
sands. 

Moulding  sands  are  obtained  in  the  coal  measures,  the 
new  red  sandstone,  and  the  green  sand  and  chalk.  As 
local  foundries  largely  use  local  supplies,  a  knowledge  of 
the  precise  mixing  of  sands  for  any  one  locality  has  to 
be  acquired  there,  and  the  experience  thus  gained  is 
modified  to  be  of  service  when  the  sands  of  another 
locality  are  employed.  Nevertheless,  there  are  certain 
general  principles  to  be  observed  in  the  mixing  and  use 
of  sands,  which  apply  to  all  alike. 

The  terms  green,  dry,  loam,  floor,  Hack,  strong,  weak, 
core,  facing,  burnt,  parting,  road  sands,  have  exclusive 
reference  to  mixtures,  and  physical  conditions;  none 
whatever  to  geological  character,  or  to  locality. 

Sand  is  green  when-  the  mixture  is  used  in  its  natural 
condition,  that  is,  damp,  or  mixed  with  just  sufficient 
water  to  render  it  coherent.  Immediately  after  the  pattern 
has  been  withdrawn  therefrom,  the  mould  is  ready,  ex- 
cept for  the  necessary  cleaning  and  mending  up,  and 
blackening,  to  receive  the  metal.  It  is  also  termed  weak 
sand  to  distinguish  it  from  the  other  mixtures,  which  by 
comparison  therewith  are  strong,  i.e.,  possessed  of  superior 
binding  qualities — having  more  body — more  coherence. 

Floor  sand, — Every  time  that  a  casting  is  poured,  the 


SANDS,  AND  THEIR  PREPARATION  7 

sand  in  the  mould  becomes  baked  dry  by  the  heat  of  the 
metal,  and  before  being  allowed  to  mingle  with  the  floor 
sand  it  is  passed  through  a  riddle  to  free  it  from  small 
particles  of  metal,  lifters,  nails,  etc.,  and  is  then  moistened 
with  water  from  a  bucket  or  can,  or  hose  pipe,  and  dug 
over  two  or  three  times,  and  it  is  then  ready  for  use  once 
more.  The  floor  sand  or  black  sand,  therefore,  forms  an 
accumulation,  always  damp,  always  ready  for  filling 
boxes,  or  for  moulding  patterns  by  a  process  of  bedding- 
in.  It  possesses  no  strength,  and  is  only  used  for  box- 
filling. 

When  a  mould  requiring  a  fine  sand  is  large,  or  only 
of  moderate  size,  then  the  common  sand  would  be  used 
for  its  main  body— or  for  'box-filling — and  only  those 
portions  which  come  next  the  pattern,  and  for  an  inch 
or  so  away  from  it,  would  be  made  with  the  more  ex- 
pensive sand.  There  are  certain  primary  methods  of 
preparing  sands  which  are,  however,  followed  in  all  shops, 
no  matter  what  kinds  or  what  proportions  are  used. 
Except  for  mere  box-filling,  no  sand  is  ever  used  just  in 
the  condition  in  which  it  is  dug  out  of  the  quarry  or  pit. 
It  is  mixed  with  other  sands,  or  other  ingredients,  and 
with  water.  Omitting  loam  mixtures  we  may  therefore 
divide  all  prepared  moulding  sands  into  two  classes,  those 
which  are  used  for  box-filling,  and  those  employed  for 
facing. 

In  reference  to  the  first,  little  preparation  is  required. 
The  floor  of  a  foundry  is  composed  entirely  of  sand, 
which  is  being  used  and  cast  into  over  and  over  again, 
year  after  year,  and  only  such  portions  as  become  burnt 
by  direct  contact  with  the  castings  are  ever  removed  and 
thrown  away.  This  sand  is  receiving  continual  addi- 
tions of  new  facing  sand,  used  once  in  contact  with  the 


8  PRACTICAL  IRON  FOUNDING 

castings,  and  then,  excepting  the  burnt  portions,  allowed 
to  mingle  with  the  floor  sand. 

Facing  sand. — The  actual  sand  which  is  rammed 
around,  and  in  immediate  contact  with,  the  pattern,  is 
termed  facing  sand,  because  it  forms  the  actual  faces  of 
the  mould,  against  which  the  metal  is  poured.  This  is  the 
true  moulding  material,  on  the  composition  and  character 
of  which  the  quality  of  the  casting  itself  depends  in  a 
very  large  measure,  and  which  is  varied  by  the  skill  and 
experience  of  the  founder  to  suit  different  classes  of 
work.  Facing  sands  are  made  to  vary  in  strength, 
porosity,  and  binding  qualities,  for  different  kinds  of 
work,  the  reasons  of  which  will  be  apparent  as  we  dis- 
cuss the  different  kinds  of  moulds.  Some  of  these  are 
more  porous  and  sharp  than  others,  and  being  open,  are 
suitable  for  light,  thin  castings,  being  more  or  less  self- 
venting.  Some  of  the  more  open  sands  are  used  alone, 
but  most  kinds  require  tempering  by  admixture  with 
those  of  opposite  qualities,  in  order  to  fit  them  for  their 
specific  uses.  Thus  strong  sands,  or  those  having  a  good 
body,  or  closeness  of  texture,  are  mixed  in  variable  pro- 
portions with  the  open  sharp  sands,  and  by  varying  their 
proportions,  sand,  like  iron,  can  be  obtained  in  any  re- 
quired grade. 

Hence  the  facing  sands  are  prepared  by  a  careful  pro- 
cess of  due  proportioning  of  ingredients  adapted  to  the 
several  classes  of  work  for  which  they  are  specially  re- 
quired. 

For  light,  and  for  heavy  work,  and  for  all  intermediate 
classes,  the  kinds  and  proportions  of  sands  used,  and 
the  quantity  of  coal  dust  intermixed,  will  vary,  and  even 
in  different  parts  of  the  same  mould.  In  parts  subject  to 
much  pressure,  the  sand  should  be  close,  rammed  hard, 


SANDS,  AND  THEIR  PREPARATION  9 

and  well  vented;  and  in  sections  where  the  opposite 
conditions  exist,  the  sand  may  be  light  and  open.  It  is 
therefore  impossible  to  give  any  precise  rules.  But  the 
broad  principles  upon  which  such  mixtures  are  propor- 
tioned can  be  indicated. 

For  lieary  moulds — that  is,  moulds  for  massive  cast- 
ings— the  sand  will  be  mixed  dense  and  strong  to  resist 
the  great  pressure  and  heat;  in  light  moulds  it  will  be 
more  porous  and  weak.  In  the  first  case  more,  in  the 
latter  less,  venting  will  be  required.  In  heavy  moulds 
more,  in  light  moulds  less,  coal  dust  will  be  used;  because 
the  burning  action  is  more  intense  in  the  former  than  in 
the  latter,  the  action  of  the  hot  metal  being  continued 
longer  in  the  case  of  the  first  than  in  that  of  the  second. 
In  a  heavy  mould,  the  proportions  of  coal  dust  may  be 
one  to  six  or  eight  of  sand;  in  light  moulds  it  may  be  one 
to  fifteen  of  sand.  The  reason  of  its  use  is  as  follows : 

Molten  metal  slightly  fuses  the  surface  of  sand  with 
which  it  comes  into  contact,  and  the  casting  becomes 
roughened  in  consequence.  A  perfectly  refractory  sand 
cannot  be  employed,  there  must  be  a  certain  percentage 
of  alumina  and  metallic  oxides,  which  are  binding  ele- 
ments, present,  to  render  it  coherent  and  workable,  and 
these  happen  to  be  readily  fusible.  The  more  silica  pre- 
sent in  a  sand  the  more  refractory  it  is;  but  too  large  a 
percentage  of  this  in  a  moulding  sand  would  diminish 
its  necessary  cohesive  property.  The  facing  sand  there- 
fore is  introduced  into  a  mould  to  supply  that  which  is 
lacking  in  the  main  body  itself,  and  by  forming  a  back- 
ing of  an  inch  or  two  in  thickness  to  the  mould,  pre- 
vents, by  the  oxidation  of  the  coal  dust,  this  burning  and 
roughening  from  taking  place.  The  carbon  of  the  coal 
yields  with  the  oxygen  of  the  air,  at  the  high  tempera- 


10  PRACTICAL  IRON  FOUNDING 

ture  of  the  mould,  either  carbonic  oxide,  or  carbon 
di-oxide,  and  the  thin  stratum  of  these  gases  largely 
prevents  that  amount  of  direct  contact  of  metal  with 
sand  which  would  produce  burning  and  roughening. 
Castings  become  sand-burnt  when  there  is  not  sufficient 
coal  dust  used  to  prevent  surface  fusion  from  taking 
place. 

Dry  sand. — Though  ordinary  green  sand  mixtures  can- 
not be  dried  and  yet  retain  coherence,  mixtures  of  close 
heavy  sands  are  made,  which  when  dried  in  the  stove, 
are  comparatively  hard  and  firm.  Only  the  heavier  sands 
of  close  clayey  texture  will  bear  drying:  green  sand  mix- 
tures would  become  friable  and  pulverize  under  the 
action  of  heat.  There  is  a  superficial  or  skin  drying  prac- 
tised with  these.  But  that  only  affects  the  surface,  and 
is-  quite  distinct  from  the  drying  to  which  the  present 
remarks  have  reference.  Horse  manure,  cow  hair,  or 
straw  are  mixed  with  dry  sand  to  render  its  otherwise 
close  texture  sufficiently  open  for  venting:  the  un- 
digested hay  in  the  manure  becoming  partially  car- 
bonized during  the  drying  of  the  mould,  while  the 
moisture  also  evaporates  at  the  same  time.  Coal  dust 
is  added  to  dry  sand  mixtures  as  to  green  sand.  It  is 
said  to  be  strong  to  distinguish  it  from  weak  or  green 
sand.  It  is  a  mixture  which  is  used  for  a  better  class 
of  moulds  than  green  sand.  It  is  also  specially  adapted 
for  heavy  work.  Less  gas  is  generated  by  the  use  of 
dry  than  of  green  sand,  and  the  mould  is,  therefore, 
safer.  It  is  mixed  damp,  and  rammed  like  ordinary 
facing  or  moulding  sand,  but  is  dried  in  the  core  stove 
previous  to  casting.  Being  dried,  it  is  hard,  and  will 
stand  a  greater  degree  of  liquid  pressure,  approximating 
in  these  respects,  and  in  being  mixed  with  horse  manure, 


SANDS,  AND  THEIR  PREPARATION  11 

to  loam.  But  it  differs  from  loam  in  containing  coal 
dust,  and  in  being  rammed  damp,  like  green  sand,  around 
a  complete  pattern. 

Core  sand. — This  is  variously  mixed.  For  light  and 
thin  castings  it  is  open  and  porous,  being  chiefly  or 
entirely  moulding  sand,  and  having  just  sufficient  co- 
hesiveness  imparted  to  it  by  the  addition  of  clay  water, 
peasemeal,  beer  grounds,  or  other  substances,  to  make  it 
bind  together.  But  for  heavy  work,  and  that  which  has 
to  stand  much  pressure,  strong  dry  sand  mixtures, 
having  horse  manure,  are  used.  It  is  always  rammed 
damp,  like  moulding  sand,  and  dried  similarly  to  dry 
sand  moulds.  Cores  are  also  made  with  loam  by  sweeping 
up  or  striking  up. 

Loam. — This  is  a  mixture  of  clayey  and  of  open  sands 
ground  up  together  in  proportions  varying  with  the 
essential  nature  of  those  sands.  It  is  a  strong  mixture, 
which  is  wrought  wet,  and  struck  up  while  in  a  plastic 
condition,  and  being  afterwards  dried,  forms  a  hard, 
compact  mould.  The  close  texture  of  the  loam  is  not 
vented,  as  is  usual  with  green  and  dry  sand  moulds,  with 
the  vent  wire;  but  certain  combustible  substances  are 
mixed  and  ground  up  with  the  sand,  and  these,  in  the 
drying  stove,  become  carbonized,  leaving  the  hard  mass 
of  loam  quite  porous.  The  material  usually  employed  is 
horse  manure,  containing,  as  it  does,  a  large  proportion 
of  half  digested  hay.  Straw,  cow  hair,  and  tow  are  also 
employed ;  but  the  horse  manure  appears  to  be  almost 
universally  made  use  of.  Loam  is  used  in  different 
grades,  being  coarser  for  the  rough  sweeping  up  of  a 
mould,  and  for  bedding-in  the  bricks,  than  for  facing  and 
finishing  the  surface.  Old  loam,  that  is,  the  best  un- 
burnt  portions  stripped  from  moulds  which  have  been 


12  PRACTICAL  IRON  FOUNDING 

cast  in,  is  also  ground  up  again  with  new  sands,  and 
used  both  in  loam  and  dry  sand  mixtures.  Loam,  unlike 
the  other  mixtures,  has  no  coal  dust  mixed  with  it. 

Parting  sand. — This  is  burnt  sand,  used  for  making 
the  joints  between  sections  of  moulds,  which,  without  the 
intervention  of  the  parting  sand,  would  stick  together. 
The  sand  is  red  sand,  baked,  or  brick-dust,  or  burnt  sand 
scraped  from  the  surface  of  castings.  A  thin  layer  only, 
of  no  sensible  thickness,  is  used.  Its  value  consists  in  its 
non-absorption  of  moisture,  so  that  it  forms  a  dry,  non- 
adhesive  stratum  between  damp  and  otherwise  coherent 
faces.  Parting  sand  is  simply  strewn  lightly  and  evenly 
over  with  the  hand. 

I  have  not  given  definite  proportions  of  sands  for 
different  mixtures,  because  the  proportions  of  such  mix- 
tures must  depend  entirely  upon  locality  as  well  as  upon 
the  class  of  work  for  which  they  are  intended.  The  red 
sand  or  the  yellow  sand  of  one  locality  will  not  be  pre- 
cisely like  that  of  another,  and  therefore  the  practice 
will  differ  in  different  parts  of  the  country.  Moreover, 
the  mixture  of  sands,  like  that  of  metals,  is  largely  a 
matter  of  individual  opinion  and  experience;  each 
foundry  foreman  follows  the  practice  which  in  his  ex- 
perience has  produced  the  best  results.  And  again,  green 
sand,  dry  sand,  and  loam  mixtures  are  each  prepared  in 
various  grades  to  suit  different  classes  of  work,  differ- 
ences of  strength  or  body  being  required,  not  only  in 
distinct  moulds,  but  even  in  individual  portions  of  the 
same  mould.  As  generally  indicative  only  of  the  methods 
and  proportions  of  mixing  adopted,  a  few  recipes  are 
given  in  the  Appendix. 

Facings. — The  use  of  facing  sand  is  not  sufficient  alone 
to  ensure  a  clean  face  or  skin  on  castings.  Hence  a  thin 


SANDS,  AND  THEIR  PREPARATION  13 

film,  a  facing,  or  a  paint  of  a  carbonaceous  substance,  is 
always  brushed  over  moulds,  excepting  those  intended 
for  castings  of  the  roughest  possible  character.  This 
film  will  be  laid  on  wet  or  dry,  according  to  the  class  of 
work.  It  is  comprised  of  different  ingredients  also. 
Formerly  the  facings  or  paints  were  mostly  made  of 
ground  wood-charcoal  and  coal-dust.  At  that  time  the 
moulder  mixed  his  own  facings  to  suit  different  kinds  of 
work,  and  the  muslin  blacking-lag  was  in  frequent  re- 
quisition. Now,  various  preparations  are  ground  and 
mixed,  and  sold  under  different  names,  for  specific  pur- 
poses. In  the  best  foundries  now,  also,  nearly  pure 
plumbago  or  black-lead  is  used  almost  exclusively. 
Though  costly,  it  produces  a  finer  skin  than  the  prepara- 
tions of  charcoal  and  coal-dust,  and  is  less  troublesome 
to  apply.  It  is  dusted  over  the  mould,  and  swept  with  a 
broad  camel-hair  brush,  and  then  sleeked  with  the 
trowel.  On  green-sand  moulds  nothing  more  is  required, 
because  the  porous  face  of  the  sand  retains  the  plum- 
bago. But  on  all  dried-sand  and  loam  moulds,  and  on 
the  faces  of  skin-dried  green-sand  moulds,  the  plumbago 
is  made  into  a  wash  with  water  and  clay,  or  other 
cementing  substances.  But  on  moulds  of  this  kind,  the 
paint,  as  it  is  called,  is  generally  made  of  the  cheaper 
coal-dust  mixed  into  a  black  ivash  or  wet  blacking,  with  the 
clay  water,  the  clay  in  the  water  binding  the  dust  and 
preventing  it  from  fiaking  off  when  in  the  stove.  Since  the 
best  plumbago  costs  something  like  £1  per  cwt.,  or  about 
twenty  times  as  much  as  coal-dust,  there  is  reason  for  such 
economy.  It,  however,  always  peels  better  than  the  coal- 
dust  or  charcoal-dust — that  is,  the  sand  can  be  stripped 
from  the  casting  more  freely,  leaving  a  smoother  face, 
hence  for  good  work  it  has  superseded  the  common  blackings. 


14  PRACTICAL  IRON  FOUNDING 

There  is  much  difference  in  the  cost  of  foundry  black- 
ings, the  price  increasing  with  the  amount  of  pure  black- 
lead  present.  All  grades  are  obtainable,  for  green  sand 
and  loam,  for  light  and  fancy  work,  and  for  general  and 
heavy  work. 

There  is  no  need  to  use  a  large  quantity  of  blacking 
or  plumbago  on  a  mould.  It  tends  to  roll  up  before  the 
metal,  and  form  streaky  lines  or  rough  patches,  which 
are  unsightly.  Neither  should  it  be  sleeked  much,  for 
much  sleeking  is  always  injurious  to  the  face  of  a  mould. 
Passing  the  trowel  over  it  once  or  twice  only  lightly  is 
sufficient  to  make  it  lay  to  the  mould.  It  is  put  on  dry- 
sand  and  loam  moulds  after  they  have  been  dried  in  the 
stove,  and  while  yet  warm.  If  the  moulds  are  allowed  to 
get  cold  first,  then  the  blacking  must  be  dried  off. 

The  effect  of  the  blacking  is  to  prevent  the  metal  from 
being  roughened  by  direct  contact  with  the  sand.  The 
plumbago  facing  acts  so  efficiently  that  often  when  a 
casting  is  turned  out,  if  the  fingers  are  rubbed  on  it,  the 
plumbago  adherent  to  its  surface  will  come  off  on  the 
fingers,  showing  that  it  has  remained  unaffected  by  the 
heat.  This  protection  has  nothing  to  do  with  the  pro- 
duction of  sound  castings,  but  it  improves  the  appear- 
ance immensely. 

Chemistry  of  sands. — The  time  has  not  arrived  when 
chemical  analysis  can  displace  the  practical  knowledge 
gained  by  experience  in  working  in  particular  grades  of 
sands.  Analysis  safely  asserts  that  the  purest  sands 
should  consist  of  little  besides  silica  and  alumina,  the 
first  the  refractory  element,  the  second  the  bond.  Lime 
and  iron  oxide,  with  the  alkalies — soda,  potash,  and 
sometimes  traces  of  other  ingredients — all  detract  from 
the  value  of  a  sand,  lowering  the  fusing  point  and  ren- 


SANDS,  AND  THEIR  PREPARATION  15 

dering  it  liable  to  flux.  If  the  materials  in  a  sand 
become  fused  by  the  molten  metal  the  result  will  be 
the  closing  of  the  pores,  so  preventing  the  escape  of  the 


Sizes  of  grains. — If  the  grains  are  large  and  regular 
in  size  and  shape  the  sand  will  be  more  porous  than 
with  opposite  conditions.  The  popular  objection  to  large 
grains  is  that  they  will  not  produce  castings  with  smooth 
skins.  Also  grains  of  equal  size  and  of  angular  shapes 
favour  porosity,  while  grains  of  unequal  sizes,  and  which 
have  smooth  surfaces,  do  not,  though  they  give  a  strong 
sand. 

Alumina  or  clay,  being  hydrated  silicate  of  alumina, 
contains  46.4  per  cent,  of  silica,  39.7  per  cent,  of  alumina, 
and  13.9  per  cent,  of  combined  water,  so  that  the  total 
silica  is  a  larger  quantity  than  the  free  silica. 

Mechanical  analysis  deals  with  the  sizes  of  sand  grains, 
and  is  very  useful  because  it  reveals  the  texture  of  the 
sand,  which  is  passed  through  a  succession  of  sieves  of 
different  meshes,  and  the  proportions  which  pass  through 
the  different  meshes  afford  data  for  estimating  the  suit- 
ability of  the  sand  for  fine  and  coarse  work.  Weak  sands 
are  fine  grained  and  usually  have  least  alumina.  They 
are  used  for  light  green  sand  work.  For  heavy  green 
sand  work  a  larger  proportion  of  alumina  is  desirable, 
and  coarser  grained  sands.  For  dry  sand,  loam,  and 
cores,  the  largest  proportion  of  alumina  is  suitable,  and 
fine  sand.  That  castings  with  smooth  skins  cannot  be 
obtained  from  coarse  sands  is  negatived  by  experience. 
The  coarse  grains  favour  the  escape  of  the  gases,  and 
the  applications  of  facings  fill  up  the  spaces  against 
which  the  metal  is  poured.  The  following  are  analyses 
of  standard  sands  used  for  different  kinds  of  work. 


16  PRACTICAL  IRON  FOUNDING 

Sand  for  fine  castings 

Silica 81.50  per  cent. 

Alumina 9.88         ,, 

Iron  Oxide 3.14 

Lime 1.04 

Magnesia 0.65         ,, 

(Fine  grain) 

Sand  for  average  castings 

Silica 84.86  per  cent. 

Alumina 7.03 

Iron  Oxide 2.18 

Lime 0.62 

Magnesia 0.98         „ 

(Medium  grain) 

Sand  for  heavy  castings 

Silica 82.92  per  cent. 

Alumina   .......       8.21 

Iron  Oxide 2.90 

Lime 0.62 

Magnesia 0.00 

(Coarse  grain) 

But  Heinrich  Eies  has  stated  that  there  is  no  relation 
between  the  bonding  power  and  plasticity,  and  the  per- 
centage of  alumina,  as  determined  by  chemical  analysis. 
He  says  that  the  mechanical  analysis  affords  an  approxim- 
ate index  of  the  cohesiveness  of  sand.  In  this  analysis  the 
grains,  being  passed  through  sieves  of  different  mesh, 
yield  percentages  of  the  grains  retained  in  each,  while 
the  clay  group  forms  another  percentage  separated  from 
the  sand  grains. 

The  texture  of  a  sand  has  a  much  greater  influence 


SANDS,  AND  THEIR  PREPARATION  17 

on  its  suitability  for  a  given  class  of  work  than  the 
chemical  analysis.  Heinrich  Eies  illustrates  this  fact 
by  giving  four  sets  of  chemical  and  mechanical  analyses 
of  sands,  as  below.  In  these  Nos.  1  and  2  agree  closely 
in  their  chemical  composition,  but  differ  in  their  texture. 
Nos.  3  and  4  agree  closely  in  chemical  analysis,  but  differ 
widely  in  mechanical  analysis.  No.  1  was  Albany  sand 
used  for  stove  plate  work.  No.  2,  stove  plate  sand  from 
Newport,  Ky.  No.  3,  sand  for  general  work  from  Peters- 
burg, Ya.  No.  4,  sand  for  general  work  from  Fredericks- 
burg,  Va. 

Chemical  analyses 

No.  1       No.  2        No.  3  No.  4 

Silica 79.36      79.38      84.40      85.04  per  cent. 

Alumina.  .  .  .  9.36  9.38  7.50  5.90  „ 
Ferric  Oxide  .  .  3.18  3.98  2.52  3.18  „ 

Lime 0.44        1.40        0.06        0.06       „ 

Magnesia      .     .     .       0.27        0.54        0.21        0.14 
Potash     ....       2.19        1.80        1.29        1.65 

Soda 1.54        1.04        0.65        0.83 

Titanic  Oxide  .  .  0.34  0.44  0.44  0.78  „ 
Water  ....  2.02  2.50  1.49  1.57  „ 
Moisture.  0.74  0.80  1.76  1.11 


Mechanical  analyses 

PER  CENT.  RETAINED 

Size  Mesh. 

1. 

2. 

3. 

4. 

20    ... 

0.26 

0.06 

0.09 

0.19 

40    ... 

0.51 

0.12 

0.41 

0.19 

60    ... 

2.53 

0.32 

2.21 

0.39 

80    ... 

0.99 

0.16 

2.67 

0.19 

100    ... 

4.19 

0.83 

17.37 

0.98 

250    .     .     . 

79.85 

23.38 

58.20 

81.92 

Clay    .     .     . 

11.24 

24.73 

19.02 

15.97 

C 

18  PRACTICAL  IRON  FOUNDING 

Other  materials. — Small  quantities  of  certain  very  es- 
sential articles  are  used  in  foundries,  as  clay,  resin, 
flour,  oil,  tar,  straw,  hay,  tow,  etc.  The  use  of  the 
first  three  is  chiefly  that  of  cementing  agents  for  cores. 
Small  cores  are  cemented  with  these,  the  resin  and 
flour  binding  the  sand  together,  heer  grounds  and  mo- 
lasses being  used  for  the  same  purpose.  Specially  pre- 
pared "  core  gums,"  the  elements  of  which  are  only 
known  to  the  manufacturers,  are  sold.  Clay,  mixed 
with  water  to  various  degrees  of  consistence,  is  a  valu- 
able cement  for  sticking  the  joints  of  cores  together; 
for  swabbing  flasks,  the  better  to  retain  the  sand;  for 
cementing  broken  edges  of  moulds  and  cores;  for  mix- 
ing with  wet  blacking;  and  for  other  purposes.  Oil  is 
used  for  pouring  over  the  faces  of  chaplets,  over  the 
damp  mended-up  parts  of  moulds,  and  around  metallic 
stops  in  order  to  lessen  the  risk  of  blowing  occurring  in 
those  localities,  the  metal  lying  more  quietly  on  the  oil 
than  on  the  bare  metal  or  on  the  moist  sand.  Tar  is 
used  for  painting  over  the  ends  of  wrought-iron  arms  or 
shafts  around  which  metal  has  to  be  cast,  and  for  paint- 
ing loam  patterns  to  harden  their  surfaces.  Straw  and 
hay  are  used  for  cores,  being  first  spun  into  bands, 
which  are  then  wound  round  the  core-bar.  These  are 
usually  spun  in  the  foundry,  but  can  also  be  purchased 
ready  for  use.  Tow  is  wound  round  those  portions  of 
bars  where  the  spun  bands  would  be  too  thick.  Hay  is 
also  used  in  layers  in  cinder  beds  to  prevent  the  sand 
from  filling  up  the  interstices  of  the  cinders. 

Sand  preparation. — To  prepare  and  mix  sands  various 
methods  are  made  use  of.  For  the  floor  sand,  simply 
moistening  with  water  and  turning  over  two  or  three 
times  with  the  shovel  suffices  in  most  shops.  But  all 


SANDS,  AND  THEIR  PREPARATION  19 

facing  sands  have  to  be  thoroughly  pulverized  and  passed 
through  sieves  of  varying  sized  mesh,  according  to  the 
class  of  work  for  which  they  are  required.  Sand  as  it 
comes  from  the  quarry  is  gritty  and  lumpy,  and  is 
riddled  to  separate  the  lumps,  which  are  either  thrown 
aside,  or  ground  and  crushed  and  re-riddled.  The  suit- 
able mixtures  of  sand  and  coal-dust  having  been  made, 
they  are  thoroughly  intermixed  with  water,  and  are  then 
ready  for  use. 

In  reference  to  the  watering,  it  is  as  well  to  remark 
that  this  must  not  render  the  sand  wet,  which  would 
spoil  any  mould  in  which  ifc  might  be  used,  but  only 
moist,  or  damp,  rendering  it  sufficiently  coherent  for 
moulding  into.  So  that  if  a  portion  of  such  sand  is 
taken  up  in  the  hand  and  squeezed,  it  will  retain  the 
impression  imparted  without  falling  apart  of  itself, 
which  perfectly  dry  sand  would  do. 
.  Machines. — The  growth  of  machinery  for  dealing  with 
sands  has  been  very  rapid  in  recent  years.  Old  methods 
have  been  extended,  new  ones  have  been  introduced.  The 
scores  of  designs  made  may  be  roughly  classified  under 
four  heads :  Machinery  for  sand  drying,  for  grinding,  for 
disintegrating,  and  for  riddling  and  sifting. 

Machines  for  sand  drying  are  of  cylindrical  form,  of 
rotary  designs,  in  which  the  wet  sand  fed  in  at  one  end 
through  a  hopper  is  conveyed  to  the  other,  the  cylinder 
being  disposed  at  an  angle  with  the  horizontal.  During 
its  passage  it  is  subjected  to  a  current  of  hot  air.  Several 
tons  of  sand  can  be  treated  thus  daily. 

Machines  for  grinding  sand  are  usually  of  the  type 
employed  for  grinding  loam.  This  is  essentially  a  mortar- 
mill,  having  two  heavy  grinding  rollers,  plain  or  grooved, 
between  which  and  the  bottom  of  the  pan  the  materials 


20 


PRACTICAL  IRON  FOUNDING 


are  crushed  and  ground.  The  rollers  rotate  on  their  hori- 
zontal axes,  and  either  the  rollers,  or  the  pan,  revolve 
on  their  vertical  axis,  either  being  driven  by  bevel  gears. 
Sands  are  ground  dry,  and  loam  wet  in  these  machines. 
The  pan  is  emptied  by  opening  a  door  in  the  side  near 
the  bottom. 

In  the  disintegrating  machines  the  sand  is  knocked 
about  between  rapidly  revolving  prongs  in  the  same  or 


1. — SELLERS  SAND  MIXER. 

in  opposite  directions,  being  thrown  outwards  by  centri- 
fugal force.  Early  machines  were  the  Schiitze  and  the 
Sellers.  Later  ones  more  often  have  two  sets  of  prongs, 
in  which  both  sets  may  revolve,  each  in  an  opposite 
direction  to  the  other,  or  one  may  revolve  and  the  other 
be  fixed.  The  speed  of  revolution  is  very  high,  and 
lumps  are  broken  up  effectively. 

The   Sellers   sand-mixing   machine    (Fig.    1)    operates 
centrifugally.    The  machine  is  circular,  and  the  sand, 


SANDS,  AND  THEIR  PREPARATION 


21 


on  being  thrown  in  through  a  hopper,  A,  falls  among 
a  number  of  vertical 
prongs  standing  up  from 
a  revolving  plate,  B. 
The  prongs  prevent  the 
passage  of  stones,  and 
disintegrate  the  sand  in 
its  passage  outwards. 
By  the  covering  plate, 
C,  it  is  thrown  to  the 
ground  beneath.  The 
driving  of  the  vertical 
shaft  is  done  by  belt 
pulley,  set  either  above 
or  below  the  machine, 
as  most  convenient,  or 
by  electric  motor  as  in 
the  Fig.  The  rate  of 
revolution  of  the  shaft 
is  about  1,200  revolu- 
tions per  minute.  The 
hopper  is  hinged,  and 
can  be  thrown  back  when 
necessary  for  the  re- 
moval of  obstructions. 
There  is  but  little  differ- 
ence between  Schiitze's 
sand-mixer  (Fig.  2)  and 
that  of  Messrs.  Sellers. 
In  this  mixer,  vertical  Fm  2.— THE  SCHUTZE  MIXER. 
prongs  on  a  rapidly  re- 
volving plate,  B,  break  up  the  sand  falling  through  the 
hopper  by  centrifugal  force.  A  is  the  hopper,  C  the 


22 


PRACTICAL  IRON  FOUNDING 


shaft  driven  by  a  pulley,  I).  An  indiarubber  guard  round 
the  machine  throws  the  sand  downwards.  The  hopper 
and  cover  (attached  to  each  other)  can  be  thrown  back 
on  a  hinge  to  expose  the  plate,  B. 

Fig.  3  illustrates  a  horizontal  class  of  disintegrating 
mixer  with  double  cages  rotating  in  opposite  directions, 
driven  by  separate  pulleys.  The  hollow  shaft  which 
carries  one  cage  runs  in  dust-proof  ball-bearings,  and  the 
inner  shaft  is  fitted  in  ring-oiling  white-metal  bearings. 


FIG.  3. — DOUBLE  CAGE  DISINTEGRATOR. 

The  sand  is  fed  in  through  the  shute  at  the  side,  and  the 
hood  is  hinged  to  enable  it  to  be  thrown  back  for  clean- 
ing purposes.  The  machine  is  constructed  by  Messrs. 
Alfred  Gutmann,  A.G. 

In  mixing  sand  we  seldom  find  moulders  using 
weights  or  legal  measures.  It  is  always  measured  in 
"barrows,"  "  sieves,"  "  riddles,"  "buckets  " — those  being 
the  utensils  in  common  use  in  foundries. 

The  mixing  is  done  by  hand  riddles  and  sieves,  or  by 
mechanisms.  The  first  are  employed  in  small  shops. 


SANDti,  AND  THEIR  PREPARATION  23 

The  only  difference  between  a  riddle  and  a  sieve  is  one  of 
size  of  mesh.  Both  alike  are  circular,  but  while  riddles  em- 
brace meshes  down  to  TV  in.,  sieves  cover  sizes  below 
these.  A  screen  is  used  only  to  separate  the  coarse  lumps 
from  the  sand  at  the  time  of  delivery  from  the  quarry. 

The  sand  is  intermixed,  riddled,  or  sieved  by  hand 
upon  a  rude  horse  formed  of  wrought-iron  bars.  The 
riddle  or  sieve  is  thrust  backwards  and  forwards,  along 
the  top  bars,  the  sand  falling  on  the  ground  below,  whence 
it  is  removed  to  the  heaps,  or  to  the  sand  bins,  which  are 
large  recesses  conveniently  prepared  somewhere  in  the 
sides  of  the  shop  for  the  storage  of  sand  in  readiness  for 
the  moulder.  All  the  sifting  and  wheeling  away  is  done 
by  the  moulders'  labourers.  There  are  several  good 
mechanical  sifters  in  use  in  foundries,  operated  by  power 
mechanism,  which  imparts  a  rocking  motion  to  the 
sifters. 

The  swinging  sand  sifter  (Fig.  4,  shown  in  plan  and 
in  elevation),  made  for  driving  by  power,  is  suspended 
from  the  beams  of  a  roof  or  floor  above  by  loosely  hung 
sling  rods.  The  parts  are  as  follow :  A  is  the  tray  itself, 
formed  of  a  piece  of  yV  in.  plate  bent  round  to  form 
three  sides  of  a  rectangle,  the  fourth  side  being  open. 
There  are  three  rows  or  tiers  of  ^  in.  round  bars  riveted 
across,  so  pitched  out  that  the  rods  alternate  with  one 
another  in  the  vertical  direction  the  better  to  assist  in 
breaking  up  the  larger  lumps  01  sand.  Over  the  lower  row 
is  laid  the  sieve  bottom  (not  shown  in  this  figure),  the 
size  of  the  mesh  of  which  may  vary  from  £  to  1  in. 
Screwed  stay  rods  pass  across  from  side  to  side,  and  by 
means  of  those  which  come  near  the  ends,  the  straps,  J5, 
are  fastened,  to  which  the  sling  rods,  C,  are  hooked.  The 
oscillatory  motion  is  imparted  by  means  of  the  three  teeth, 


24 


PRACTICAL  IRON  FOUNDING 


D,  thrusting  against  the  pins  in  the  slotted  piece,  E.  F,  Fl 
are  the  fast  and  loose  pulleys  for  driving,  having  their 


FIG.  4. — SWINGING  SAND  SIFTER. 

shaft  bearings  in  the  bracket,  G,  bolted  to  a  wall,  or  as 
convenient.  The  tray  is  suspended  at  a  slight  angle, 
the  open  end,  or  that  farthest  from  the  driving  gear, 


SANDS,  AND  THEIR  PREPARATION 


25 


being  lowermost.  The  fine  sand  then  falls  vertically  down- 
wards through  the  sieve  into  a  bin,  while  the  larger 
lumps  pass  onwards  and  fall  out  at  the  open  end. 

Many  sieves  are  of  double  design,  with  the  primary 


FIG.  5. — COMBINED  GRINDER  AND  SIEVE. 


object  of  dealing  with  old  or  floor  sand.  Two  rectangular 
sieves,  an  upper  and  a  lower  one  of  coarser  and  finer 
mesh  respectively,  separate  lumps,  nails,  and  particles  of 
iron  from  the  sand  and  discharge  it,  while  the  fine  sand 
is  dropped  through  the  lower  sieve  and  discharged  at 


26 


PRACTICAL  IRON  FOUNDING 


one  end.  The  sieves  are  set  at  an  angle  in  opposite 
directions. 

Another  design  of  sieve  is  rotary  in  action,  and  poly- 
gonal in  outline,  with  a  rapping  device  to  assist  the  dis- 
charge. Each  of  these  designs  occurs  in  several  modifica- 
tions. 

For  grinding  coal  for  facing  sands,  and  blackening,  a 
mill  of  another  type  is  used;  this  is  sometimes  a  revolv- 
ing cylinder,  rotating  with  its  longitudinal  axis  in  the 
horizontal  position,  having  loose  heavy  rollers  inside, 


FIG.  6. — PLAN  VIEW  OF  COMBINED  GRINDEK  AND  SIEVE. 

which,  as  the  cylinder  revolves,  remain  in  the  bottom  by 
reason  of  their  weight,  and  crush  the  coal  or  coke,  intro- 
duced before  the  mill  is  started  through  a  door  at  the 
top  of  the  cylinder.  An  improved  form  is  one  in  which 
heavy  balls  are  set  revolving  within  a  pan  in  an  annular 
groove,  a  vertical  spindle  passing  through  the  cover.  The 
spindle  is  driven  through  bevel  wheels  by  a  belt-pulley. 
There  is  a  cover  of  wood  for  the  introduction  of  the  coal, 
and  to  prevent  the  flying  out  of  the  dust.  The  ground  coal 
is  taken  away  through  a  door  in  the  bottom  of  the  pan. 


SANDS,  AND  THEIR  PREPARATION  27 

A  combined  type  of  machine  is  seen  in  Figs.  5  and  6, 
comprising  an  edge-runner  grinding  pan,  and  an  octa- 
gonal sieve,  the  rollers  of  the  first  named  being  driven  by 
the  bevel  gears  on  the  top  shaft.  The  sieve  is  revolved 
by  a  belt  pulley  from  the  same  shaft.  When  the  rough 
lumpy  sand  has  been  ground  in  the  pan,  it  passes  down 
a  shute  into  the  sieve.  If  it  has  been  ground  sufficiently 
small  it  falls  through  the  meshes  and  is  removed ;  but  if 
there  are  lumps  of  too  large  a  size,  they  are  carried  up 
around  the  top  of  the  sieve,  and  fall  down  the  top  shute 
into  the  pan  again  to  undergo  further  crushing. 

Fig.  7,  PI.  I,  represents  an  electro-magnetic  separator 
in  conjunction  with  a  reciprocating  sieve,  built  by  the 
London  Emery  Works  Company.  The  rough  sand  is  fed 
into  the  hopper  at  the  top,  and  falls  on  to  the  magnetic 
drum  which  abstracts  and  retains  all  the  nails  and  other 
scraps  of  iron  or  steel  present,  after  which  the  sand  drops 
into  the  sieve,  and  is  thoroughly  shaken  and  broken  by 
the  rapid  reciprocations  until  it  is  fine  enough  to  escape 
through  the  meshes. 


CHAPTER  III 

IRON MELTING  AND  TESTING 

CAST  iron  owes  its  value  as  a  material  of  construction  to 
the  fact  that  it  is  not  pure  metal.  If  it  were  pure,  it 
would  be  useless  for  the  purposes  to  which  it  is  now 
applied.  Pure  iron  cannot  be  melted  to  fluidity,  neither 
when  cold  is  it  rigid  nor  hard,  but  ductile  and  soft  by 
comparison  with  commercial  iron.  Cast  iron  does  not 
contain  more  than  93  or  94  parts  of  pure  metal  in  the 
100,  the  remaining  6  or  7  consisting  of  carbon,  silicon, 
phosphorus,  sulphur,  and  manganese,  with  occasional 
percentages  of  arsenic,  titanium,  and  chromium. 

The  element  which  more  than  any  other  influences  the 
physical  character  of  cast  iron  is  carbon,  and  this  occurs 
in  allotropic  forms,  either  as  graphite  or  plumbago,  in  a 
state  of  mechanical  admixture,  forming  gray  iron;  or  as 
combined  or  dissolved  carbon,  producing  white  iron.  In 
most,  if  not  all  commercial  irons,  the  carbon  occurs  in  both 
forms.  The  proportion  of  combined  carbon  is  never  more 
than  a  mere  trace  in  the  gray,  while  the  white  iron 
is  almost  destitute  of  graphitic  carbon.  The  mottled 
varieties  occupy  a  position  midway  between  the  gray  and 
white,  and  are  to  be  regarded  as  mixtures  of  the  two 
kinds,  the  mottle  being  more  pronounced  as  the  propor- 
tion of  white  increases.  Here,  too,  the  proportions  of 
combined  and  graphitic  carbon  become  nearly  equalized. 
Gray  iron  is  the  most  fluid,  but  is  the  weakest.  White 

28 


IRON— MELTING  AND  TESTING  29 

iron  runs  pasty,  and  is  strong,  but  brittle.  Mottled  iron 
melts  very  well,  and  is  both  strong  and  tough. 

Iron  is  adapted  for  general  engineers'  work  in  propor- 
tion to  its  amount  of  mottle,  highly  mottled  iron  being 
correspondingly  prized  by  foundrymen. 

There  are  several  varieties  of  pig  supplied  by  the  iron- 
masters, ranging  from  the  No.  1  Clyde,  which  is  the 
grayest  iron,  to  the  forge  pigs,  which  are  white  irons 
(see  the  Appendix).  Hence  it  is  possible  to  obtain  pigs 
suited  to  almost  any  class  of  work,  being  either  used 
alone,  or  by  intermixture.  In  foundries  where  the  same 
class  of  castings  is  being  constantly  turned  out,  this  is 
what  is  done;  but  in  general  foundries,  where  all  kinds  of 
castings  are  required  in  gray,  white,  and  mottled  iron,  in 
all  their  grades,  usually  three  or  four  kinds  of  pig  only  are 
kept  in  stock,  and  the  numerous  grades  of  metal  required 
from  day  to  day,  or  during  the  same  day,  are  prepared 
by  admixture  of  pig  with  scrap.  It  is  in  these  mixtures 
that  the  skill  of  the  practical  foreman  or  furnaceman  is 
seen,  skill  which  comes  only  after  long  experience.  There 
are  many  moulders  who  would  not  know  how  to  mix 
metals  to  produce  definite  grades,  and  no  rules  can  be 
laid  down  for  this  work  except  those  of  a  somewhat 
general  character.  Thus  it  is  easy,  having  ascertained 
the  metal  which  results  from  the  mixture  of  certain  pigs 
in  certain  definite  proportions,  to  repeat  the  operation  as 
often  as  required,  since  a  grade  of  pig  of  a  given  brand 
is  fairly  though  not  absolutely  constant  in  character. 
But  when  scrap  is  used,  the  quality  of  each  separate  piece 
of  scrap  has  to  be  estimated  by  its  behaviour  under  the 
sledge,  and  by  the  eye.  The  use  of  scrap,  if  purchased 
judiciously,  and  mixed  by  a  competent  man,  is  more 
economical  than  that  of  pig,  and  there  is  therefore 


30  PRACTICAL  IRON  FOUNDING 

advantage  in  its  employment.  Every  furnaceman  and 
foreman  should  therefore  learn  to  judge  of  the  quality  of 
scrap  and  pig,  and  the  effect  of  their  intermixture.  After- 
wards he  may  test  the  results  experimentally  at  the  testing 
machine ;  but  he  must  know  how  to  mix,  or  the  testing 
machine  will  record  only  failures. 

Gray  iron  on  being  struck  with  a  sledge  fractures  easily, 
and  presents  a  highly  crystalline  structure,  with  a  some- 
what dull  bluish-gray  metallic  lustre.  If  very  dull,  the 
metal  is  inferior,  and  poor  in  quality. 

Iron  follows  the  same  law  of  crystallization  as  other 
substances.  The  slower  the  rate  of  cooling  the  larger  the 
crystals  produced.  If  a  newly  fractured  surface  of  gray 
iron  is  shaded  by  the  hand,  and  so  viewed  with  reflected 
light  only,  the  crystals  of  graphite  become  visible,  appear- 
ing as  black  lustrous  patches  amongst  the  iron.  If  a 
portion  of  the  iron  is  crushed  and  levigated,  the  graphite 
will  float  on  the  surface  of  the  water.  When  the  metal 
is  molten  it  lies  quietly  in  the  ladle,  breaking  into  large 
striations,  without  sparks  or  disturbance.  After  standing 
awhile  it  becomes  covered  with  scum,  composed  of  scales 
of  graphite  which  have  separated  and  floated  to  the  sur- 
face. When  cast,  it  runs  fluid,  and  takes  the  sharpest 
impressions  of  the  mould,  being  thus  adapted  for  the 
finest  castings.  It  is  only  moderately  contractile.  At  the 
testing  machine  it  breaks  with  a  very  moderate  load, 
undergoing  however  a  considerable  amount  of  deflection 
first.  It  can  be  tooled  easily. 

If  we  take  ivhite  iron,  whether  in  the  form  of  pig  or  of 
scrap,  and  fracture  it,  we  find  that  it  requires  more  force 
than  the  gray  to  effect  fracture,  but  that  it  breaks  very 
short  and  clean.  An  inspection  of  the  fractured  surface 
reveals  a  highly  crystalline  structure,  but  the  crystals  are 


IRON—MELTING  AND  TESTING  31 

long,  fine,  and  needle-like  in  character,  and  of  a  bright, 
almost  silvery-like  lustre:  no  scales  of  graphite  can  be 
detected.  The  melted  metal  when  in  the  ladle,  though 
thick  and  somewhat  viscous  by  comparison  with  gray 
iron,  is  in  a  state  of  violent  ebullition;  boiling,  bubbling, 
and  throwing  off  a  quantity  of  sparks  or  jumpers.  It  does 
not  run  well  except  in  considerable  mass,  and  is  highly 
contractile.  Unlike  the  gray  iron,  it  cannot  be  shaped 
with  the  chisel  and  file.  At  the  testing  machine  it  sus- 
tains a  greater  load  before  fracture  than  gray  iron,  but 
breaks  with  less  deflection. 

The  mottled  iron  being  a  mixture  of  gray  and  white, 
partakes  more  or  less  of  the  characteristics  of  each,  and 
is  therefore  better  adapted  for  most  castings  than  either 
of  those  alone.  Considerable  force  is  required  to  fracture 
a  good  sample  of  mottled  iron,  and  when  the  broken 
surface  is  examined  it  presents  that  peculiar  mottled 
appearance  from  which  it  derives  its  name.  The  crys- 
tals are  of  the  same  form  as  those  in  gray  iron,  but 
smaller,  and  the  dull  bluish  lustre  of  that  is  replaced  by 
a  more  silvery  hue.  The  colour  alternates,  being  patchy, 
the  white  contrasting  with  the  graphitic  scales  still  pre- 
sent. It  melts  and  runs  well,  is  tolerably  quiet  in  the  ladle, 
is  moderately  contractile,  takes  a  high  strain  and  a  good 
deflection  at  the  machine,  and  tools  with  average  ease. 

There  are  several  grades  of  gray,  mottled,  and  white 
irons,  and  the  skill  of  the  furnaceman  consists  in  judg- 
ing of  the  minute  differences  in  these  and  utilizing  them 
accordingly. 

There  is  a  grade  of  iron  often  found  along  with  scrap, 
known  as  burnt  iron.  It  is  metal  which,  having  been 
long  subjected  to  an  intense  heat  below  the  melting 
point,  has  lost  much  of  its  metallic  character,  being 


32  PRACTICAL  IRON  FOUNDING 

largely  in  the  condition  of  oxide.  It  is  of  an  earthy  red 
colour,  and  is  found  in  scrap  containing  old  fire  bars, 
sugar  and  soap  pans,  retorts,  and  furnace  grates.  In  the 
furnace  it  does  not  melt  freely,  but  becomes  viscous  or 
pasty,  and  chokes  the  tuyeres  and  the  fuel.  In  a  furnace 
using  much  of  this,  the  slagging  hole  has  to  be  kept  open 
during  nearly  all  the  time  of  melting,  and  much  of  the 
iron  mixes  with  and  runs  away  to  waste  with  the  slag. 
It  damages  the  furnace  lining,  and  when  poured  runs 
very  thick,  and  produces  almost  white,  but  rotten  cast- 
ings. Burnt  iron  can  only  be  properly  utilized  by  ad- 
mixture in  slight  proportions  with  good  open  gray  pig. 

The  largest  proportion  of  pig  used  for  foundry  pur- 
poses is  smelted  either  in  Scotland  from  the  Black  Band 
ironstone;  or  in  the  Cleveland  district  in  the  North  Bid- 
ing of  Yorkshire,  from  the  Cleveland  ironstone.  Smaller 
quantities  come  from  Shropshire,  Staffordshire,  South 
Wales,  and  a  few  other  localities. 

Pig  is  obtainable  in  five  or  six  grades.  No.  1  is  the 
most  gray  and  open,  and  as  the  numbers  run  up  the  iron 
becomes  closer  and  mottled,  or  white. 

Scrap. — When  a  furnaceman  or  foreman  has  to  pro- 
vide for  a  general  run  of  work,  as  is  the  case  in  nearly 
every  foundry,  there  are  usually  two  courses  open.  One 
is  to  stock  various  brands  of  pig  and  melt  from  those 
brands,  singly  or  variously  mixed,  to  suit  the  various 
kinds  of  work  on  the  floor.  Thus,  for  cylinders  and  for 
liners  a  different  quality  will  be  required  from  that  for  fire- 
bars or  ploughshare  points,  or,  again,  for  machine  fram- 
ings or  gear  wheels.  Though  each  grade  may  be  melted 
on  the  same  day,  in  the  same  cupola,  the  different  mix- 
tures required  will  be  kept  apart  in  the  cupola.  The 
ironmasters  will  send  pig  of  any  given  quality,  suitable 


PLATE  I 


See  p.  27 


FIG.  7. — COMBINED  SEPARATOR  AND  SIEVE 


See  p.  63  [Facing  p.  32 

FIG.  18. — BOOTS'  BLOWER,  MOTOR  DRIVEN 


IRON— MELTING  AND  TESTING  33 

for  any  class  of  work.  Or,  without  a  very  large  stock  of 
different  brands,  a  furnaceman  who  knows  his  business 
can,  by  judicious  mixing,  with  or  without  remelting  as 
occasion  requires,  make  up  metal  to  suit  any  job.  At  the 
two  extremes  there  are  the  soft  open  gray,  and  the  hard, 
close  white  pig.  Between  these  there  comes  every  variety 
of  gray,  mottled,  and  white.  But  in  all  foundries  a  cer- 
tain proportion  of  scrap  is  used  along  with  the  pig  for 
most  classes  of  work.  A  furnaceman  or  foreman  who 
thoroughly  understands  the  mixing  of  scrap  and  pig  is  a 
valuable  acquisition  to  a  firm,  for  he  can  not  only  improve 
the  quality  by  such  mixture,  but  can  save  much  money 
also,  because  scrap  is  often  to  be  bought  at  a  cheaper 
rate  than  pig.  There  is  this  further  advantage,  too,  that 
scrap  has  been  remelted  once  at  least,  and  therefore  the 
cost  of  such  remelting — supposing  pure  pig  would  other- 
wise have  to  be  used  and  remelted — is  saved.  Further, 
metal  is  improved  by  the  mixing  of  several  kinds  of  pig 
and  scrap,  very  much  as  hammered  scrap  is  improved  by 
the  piling  and  welding  of  all  kinds  of  bars. 

Only  when  a  furnaceman  cannot  judge  scrap  well,  is  it 
desirable  to  make  use  chiefly  of  special  brands  of  pig. 
There  must  be  some  scrap  always  used,  because  the 
runners  and  risers,  the  overflow  metal,  and  the  wasters 
have  to  be  used  again  in  any  foundry.  ^And  there  are 
few  foundries  that  do  not  use  one-third  or  one-half  scrap 
in  the  mixing  of  metal. 

Good  stocks  of  pig  and  scrap  should  be  laid  in  when 
iron  is  cheap.  Much  money  can  be  saved  by  watching 
the  markets,  and  purchasing  heavily  when  prices  are 
low.  A  look-out  should  specially  be  kept  for  good 
cheap  scrap.  A  competent  man  should  be  sent  to  see 
it  previous  to  purchase.  Water  and  gas  pipes  are 


34  PRACTICAL  IRON  FOUNDING 

about  the  worst  scrap,  old  engine  work  and  machinery 
the  best,  and  the  older  it  is,  almost  invariably  the  better 
it  is.  The  scrap  should  be  roughly  sorted  out  according 
to  quality,  and  kept  in  separate  heaps. 

The  quality  of  pig,  though  subject  to  slight  variations 
in  the  same  consignment,  is  sufficiently  well  known,  and 
there  is  little  need  to  look  at  every  bar  as  it  is  broken. 
Not  so  with  scrap.  Every  piece  of  this  must  be  judged  on 
its  own  merits.  This  is  a  rather  tedious  process,  and 
there  is  only  one  way  in  which  it  can  be  done,  and  that 
is  by  the  character  of  the  fracture,  The  opinion  is  formed 
partly  by  the  amount  of  work  it  takes  to  break  a  given 
piece,  which  is  a  measure  of  its  strength  and  toughness; 
and  partly  by  the  appearance  of  the  fractured  surface,  by 
which  the  nature  of  the  iron  is  apparent.  The  broad  ap- 
pearances of  gray,  mottled,  and  white  irons  are  familiar 
to  most;  the  furnacernan's  skill  lies  in  judging  of  minute 
variations  in  these  broad  differences.  As  a  rule,  the 
rougher  and  more  uneven  and  exfoliated  the  aspect  of  the 
fracture,  and  the  more  metallic  the  lustre,  the  stronger  is 
the  iron.  If  a  mass  of  iron  has  draws  in  it,  that  will  in- 
dicate that  the  iron  was  of  a  strong  nature,  but  was  not 
properly  fed.  If  an  iron  breaks  off  short,  and  is  dull  in 
appearance,  and  the  crystals  open,  it  is  weak  and  poor. 
Gray  weak  iron  can  be  made  stronger  by  the  addition  of 
white  or  mottled;  and  mottled  can  be  brought  back  to 
gray  by  the  addition  of  open  No.  1  Scotch  pig,  or  stove 
scrap.  Weak  iron  can  be  strengthened  by  once  or  twice 
re-melting.  Test  bars  afford  a  valuable  aid  in  estimating 
the  quality  of  a  mixture  that  is  required  for  very  specific 
purposes,  and  by  their  aid  the  foreman  is  enabled  to  keep 
a  constant  check  on  his  experimental  mixtures. 

Repeated   re-melting  of  gray  iron  tends  to  increased 


IRON— MELTING  AND  TESTING  35 

strength,  at  the  sacrifice  of  toughness  and  elasticity;  the 
re-melted  metal  approaching  to  the  white  condition. 
Hence,  after  two  or  three  re-meltings,  more  open  pig 
should  be  added  to  preserve  the  toughness  of  the  metal. 

It  is  by  admixture  therefore  that  nearly  all  the  grades 
of  cast  iron  for  foundry  service  can  be  obtained.  The 
difference  in  the  qualities  of  these  mixtures  is,  as  we 
have  stated,  due  largely  to  the  amount  and  manner  of 
occurrence  of  carbon.  In  reference  to  the  remaining  con- 
stituents of  commercial  pig,  and  the  question  of  their 
relative  influences  upon  the  metal,  it  will  be  sufficient  to 
note  very  briefly  the  leading  facts  which  the  founder 
should  know  in  relation  to  these,  and  then  pass  on  to 
the  tests  applied  to  cast  work. 

Silicon  is  one  of  the  most  valuable  elements  found 
associated  with  cast  iron.  Formerly  it  was  regarded  as 
an  enemy,  producing  brittle  and  poor  metal.  Now,  by 
mixing  certain  proportions  of  silicon  with  white  iron,  it 
is  converted  into  gray,  the  silicon  throwing  out  carbon 
from  the  combined  to  the  graphitic  condition. 

Phosphorus  is  always  present  in  pig,  and  does  no  harm 
so  long  as  it  does  not  exceed  0*5  or  O75  per  cent.;  a 
higher  proportion  tends  to  brittleness.  Phosphorus  how- 
ever renders  iron  fluid,  and  this  is  an  advantage  for 
small  castings,  but  at  the  same  time  it  renders  them 
hard. 

Sulphur  in  small  quantity  produces  mottled  iron, 
separating  carbon  as  graphite,  but  in  excess  it  causes  the 
iron  to  become  white. 

Manganese  is  undesirable,  producing  a  weak  and  white 
iron. 

Aluminium. — It  has  long  been  known  that  a  very 
small  percentage  of  aluminium,  so  little  indeed  as  *01  per 


36  PRACTICAL  IRON  FOUNDING 

cent.,  suffices  to  render  molten  wrought  iron  very  fluid, 
and  to  prevent  blow  holes  in  steel  castings.  It  is  equally 
beneficial  in  cast  iron. 

It  causes  iron  at  the  instant  of  solidifying  to  throw  out 
a  portion  of  its  combined  carbon  into  the  graphitic  con- 
dition, producing  gray  iron.  The  formation  of  the  gra- 
phite is  also  so  uniform  that  the  thin  portions  of  the 
castings  are  as  gray  as  the  thicker  portions.  In  this 
respect  it  resembles  silicon.  Since  the  aluminium  sets 
free  the  carbon  at  the  instant  of  solidification  there  is 
less  tendency  to  chill,  which  result  is  caused  by  the  run- 
ning of  metal  against  a  cold  surface,  and  the  consequent 
imprisonment  of  combined  carbon  before  it  has  time  to 
separate  as  graphite. 

When  aluminium  causes  the  separation  of  the  carbon 
at  the  instant  of  solidification,  the  scales  of  graphite  at 
the  surface  of  the  casting  act  similarly  to  blackening, 
protecting  the  surface  from  becoming  sand-burnt,  and 
therefore  producing  a  softer  skin  for  cutting  tools. 

The  presence  of  aluminium,  by  making  the  grain 
closer  and  finer,  gives  greater  elasticity,  and  reduces  the 
permanent  set. 

The  shrinkage  of  iron  is  lessened  by  the  use  of  alumin- 
ium. This  might  naturally  be  expected,  knowing,  as  we 
do,  that  gray  iron  is  less  contractile  than  white.  It 
is  a  distinct  advantage,  as  lessening  shrinkage  strains 
on  disproportionate  castings. 

Testing. — It  is  at  the  testing  machine  that  the  precise 
value  of  any  mixture  of  metal  made  is  ascertained,  and 
no  foundry  of  any  pretensions  can  afford  to  be  without 
such  an  instrument.  Testing,  in  the  hands  of  such  men 
as  Professors  Unwin  or  Thurston,  has  become  a  scientific 
work,  in  comparison  with  which  that  of  the  foundry  is 


IRON— MELTING  AND  TESTING  37 

rough  and  approximate  only.   But  this  is  nevertheless 
sufficiently  accurate  and  adequate  for  its  purpose. 

The  common  method  of  testing  is  to  cast  bars  having 
a  cross  section  of  2  in.  x  1  in.,  and  a  length  of  3  ft.  2  in. 
These  are  placed  upon  supports  3  ft.  apart,  the  2  in.  being 
in  the  vertical  direction,  and  loaded  until  they  fracture. 
Fracture  in  a  good  bar  should  not  take  place  with  a  less 
load  than  30  cwt.,  in  exceptional  instances  it  goes  as 
high  as  33  or  35  cwt.;  25  to  28  cwt.  would  indicate  a 
poor  bar.  The  amount  of  deflection  is  also  noted,  as 
being  a  measure  of  the  elasticity  of  the  metal.  It  should 
not  be  less  than  §  in.,  and  will  in  good  bars  be  as  high 
as  o  in.  The  behaviour  of  bars  cast  from  the  same 
ladleful  of  metal  in  the  same  set  of  moulds  will  often 
be  found  to  vary,  fracture  variously  occurring  within  a 
range  of  2  or  3  cwts.;  hence  it  is  the  practice  to  cast 
several  bars  for  testing,  and  take  the  average  of  the 
whole.  Test  bars  should  be  cast  from  the  same  metal, 
under  the  same  conditions  of  melting,  as  the  work  for 
which  they  afford  the  test,  and  should  be  stamped  or 
labelled  with  the  date,  and  all  particulars  deemed  of 
service.  They  should  be  cast  in  the  same  manner  as  the 
work  for  the  strength  of  which  they  are  to  be  the  index,  in 
dry  sand  if  the  work  is  in  dry  sand,  in  green  sand  if  that 
is  in  green.  The  relative  strength  of  the  bars  is  affected 
by  difference  in  dimensions,  a  bar  of  small  area  being 
relatively  stronger  than  one  of  larger  area,  the  reason 
being  that  the  chilling  effect  of  the  sand  hardens  the 
outer  skin,  and  so  raises  slightly  its  tensile  strength. 
That  which  is  often  now  regarded  as  the  standard  bar  is 
1  in.  square  and  1  ft.  long.  This  sustains  about  one  ton 
before  fracture.  Pounds  weight  on  this  bar  divided  by  84 
give  hundredweights  on  the  36  in.  +  2  in.  + 1  in.  bar;  and 


38  PRACTICAL  IRON  FOUNDING 

hundredweights  on  the  latter  multiplied  by  84  give 
pounds  on  the  former. 

Testing  machine. — A  machine  designed  for  making 
tensile,  and  also  transverse  tests  on  cast-iron  specimens, 
is  illustrated  by  Figs.  8  and  9,  being  manufactured  by 
Messrs.  W.  and  T.  Avery,  Limited,  of  Birmingham.  The 
construction  comprises  a  cast-iron  bed-plate,  with  dogs 
having  blunt  knife-edges,  these  dogs  being  adjusted 
along  to  graduations  on  the  base,  either  at  12  in., 
24  in.,  or  36  in.  between  centres.  The  base  carries  a 
cast-iron  standard,  fitted  with  hardened  steel  bearing 
blocks,  upon  which  the  fulcra  knife-edges  of  the  steel- 
yard rest.  The  wrought-iron  steelyard  is  provided  with 
knife-edges  of  hardened  steel,  and  is  graduated  up  to 
the  full  capacity  by  28  Ib.  divisions.  It  is  fitted  with  a 
sliding  poise  by  means  of  which  it  is  kept  in  equilibrium, 
and  the  strain  indicated.  The  poise  is  moved  along  by 
turning  a  small  wheel  on  its  front.  The  strain  is  put  on 
by  turning  the  hand-wheel  at  the  top,  rotating  the  screw, 
and  actuating  the  stirrup  that  carries  the  blunt  knife- 
edge  which  exerts  the  strain  on  the  specimen.  A  spring 
buffer  is  fitted  in  the  steelyard  carrier  in  order  to  min- 
imize the  shock  when  the  specimen  breaks.  A  graduated 
deflection  scale  is  provided,  by  means  of  which  the  vary- 
ing deflections  of  a  specimen  under  different  strains  can 
be  ascertained  during  the  test.  Two  series  of  gradua- 
tions are  placed  on,  one  decimally  by  -oV  in.  divisions  up 
to  1  in.,  and  the  other  by  TV  in.  divisions  up  to  1  in. 

Tensile  specimens  J  in.  in  diameter  can  be  held  in  the 
hardened  steel  grip  wedges,  for  which  size  the  capacity 
of  60  cwt.  allows  for  iron  that  will  stand  15  tons  per 
square  inch,  while  bars  of  2  in.  by  1  in.  section  or  less 
can  be  dealt  with  on  the  transverse  testing  dogs. 


M      a 


40  PRACTICAL  IRON  FOUNDING 

Testing  in  the  hands  of  an  experienced  foundryman 
reveals  a  great  deal.  For  he  not  only  notes  breaking 
strength  and  deflection,  but  also  the  aspect  of  the  frac- 
tured surfaces.  He  observes  the  extent  of  mottle  or  of 
graphite,  the  dull  or  lustrous  appearance,  homogeneity 
of  texture  or  the  opposite  condition,  the  tendency  to 
undue  hardness  or  softness,  whereby  he  learns  how  to 
make  changes  in  his  mixtures  in  order  to  insure  the 
predominance  of  certain  qualities  which  he  desires  to 
obtain.  The  iron  for  [nine-tenths  of  the  castings  made 
is  put  together  in  this  way.  Still,  the  test  bar  tells 
little  of  real  value  to  one  who  is  not  acquainted  with 
foundry  work,  and  it  might  tell  a  good  deal  more  to  the 
latter  if  used  under  a  better  method. 

There  are  other  incongruities  in  the  commonly  ac- 
cepted tests  of  bars  which  strike  one  as  rather  curious. 
There  are  a  few  impact  tests  made  in  England.  The 
value  of  impact  tests  is  not  so  great  as  in  the  case  of 
rails,  because  cast  iron  is  distrusted  for  live  loads,  unless 
the  mass  of  metal  is  so  enormously  in  excess  of  that  re- 
quired for  strength  as  to  absorb  all  injurious  vibration. 
Yet  since  most  ironwork  is  liable  to  more  or  less  of 
shock,  the  impact  test  should  be  of  even  greater  value 
than  a  purely  tensile  test,  or  a  cross  breaking  test. 

There  is  another  serious  drawback  inherent  in  foundry 
tests,  and  it  is  this:  Little  attempt  is  made  to  measure 
the  shrinkage  of  iron  by  means  of  test  bars.  Yet  many 
a  casting  is  broken  in  consequence  of  excessive  and  un- 
equal shrinkages.  Much  of  this  could  be  avoided  by  the 
use  of  iron  selected  with  suitable  reference  to  the  nature 
of  the  casting.  To  a  large  extent  this  is  done  in  practice 
by  the  observation  of  the  open  or  close  nature  of  the 
fractured  surfaces  of  test  bars,  or  of  pig  and  scrap 


IRON— MELTING  AND  TESTING  41 

selected  for  making  up  the  cast.  But  this  is  not  an 
exact  method,  such  as  would  be  afforded  by  the  meas- 
urement of  a  test  bar.  Some  testing  machines  embody 
provision  for  the  precise  measurement  of  the  shrinkage 
of  test  bars.  The  general  adoption  of  this  method  would 
go  far  to  lessen  the  internal  stresses  which  frequently 
exist  in  castings,  and  which  are  a  source  of  weakness, 
resulting  often  in  serious  danger. 

Further,  since  such  great  emphasis  is  laid  by  metal- 
lurgists upon  the  influence,  injurious  or  otherwise,  of  the 
presence  of  small  percentages  of  foreign  elements  upon 
cast  iron,  a  very  distinct  advance  has  been  made  in  this 
direction  by  Mr.  Keep,  of  Detroit,  a  brief  account  of 
whose  methods  follow.  Not  by  analysis,  but  through 
physical  results,  can  the  founder  learn  best  how  to  grade 
his  irons  for  their  specific  and  varied  purposes. 

The  methods  of  testing  adopted  by  Mr.  Keep  may  be 
briefly  summarized  as  follows: 

Though  based  on  chemistry,  they  can  be  applied  by 
anyone  who  has  no  knowledge  of  chemical  reactions  or 
of  analysis.  The  basis  of  the  system  is  the  power  which 
silicon  possesses  of  causing  carbon  in  iron  to  pass  during 
cooling  from  the  combined  into  the  graphitic  condition. 
So  that,,  given  an  iron  with  a  sufficient  percentage  of 
total  carbon,  it  is  possible  to  so  vary  the  quantities  of 
silicon  added  as  to  produce  irons  in  which  the  relative 
proportions  of  combined  and  graphitic  carbon  shall  be 
graded  to  suit  any  classes  of  foundry  work.  Mainly, 
Mr.  Keep  makes  the  shrinkage  of  the  iron  the  crucial 
test.  If  equal  shrinkages  can  be  produced  in  different 
mixtures  of  iron,  then  each  mixture  will  have  similar 
qualities  'as  regards  strength,  hardness,  or  softness. 
Moderate  variations  in  the  proportions  of  manganese, 


42  PRACTICAL  IRON  FOUNDING 

sulphur,  and  phosphorus  are  of  little  or  no  practical 
consequence,  provided  the  combined  and  graphitic  car- 
bons are  suitably  proportioned,  and  this  is  evidenced  by 
the  shrinkage.  When  silicon  is  added  it  changes  com- 
bined carbon  into  graphite,  and  the  casting  occupies  a 
larger  volume  than  it  would  previously  have  had.  All 
the  founder  has  to  do  is  to  be  sure  that  there  is  sufficient 
combined  carbon  for  the  silicon  to  act  upon,  and  through. 
Silicon  alone  would  increase  shrinkage  and  harden  iron, 
but  when  acting  through  carbon  it  produces  an  exactly 
contrary  effect. 

Making  the  crucial  test  one  of  shrinkage  is  one  which 
is  consonant  with  experience.  Since  hard  white  iron 
shrinks  more  than  soft  gray  iron,  and  since  the  former 
contains  its  carbon  mainly  in  the  combined  form,  and 
the  latter  mainly  in  the  graphitic  form,  a  hard  iron  can 
be  changed  into  a  soft  one  by  causing  the  carbon  to 
separate  out  as  graphite.  Silicon  effects  this  change, 
and  therefore  indirectly  silicon  added  to  hard  white  iron 
makes  it  soft  and  gray  and  diminishes  its  shrinkage.  If, 
further,  uniformity  of  shrinkage  and  hardness  is  secured 
in  several  different  irons  by  the  addition  of  variable  pro- 
portions of  silicon,  the  irons  will  be  all  equally  graded 
for  foundry  purposes.  The  larger  the  mass  in  a  casting, 
other  conditions  remaining  the  same,  the  less  silicon 
will  be  required,  because  the  cooling  is  slower,  and  the 
carbon  has  more  time  to  separate  out  as  graphite.  The 
more  carbon  present,  the  less  silicon  will  be  required, 
because  the  presence  of  plenty  of  carbon  is  favourable 
to  the  separation  of  graphite. 

It  is  not,  however,  that  a  certain  percentage  of  silicon 
is  necessary  to  produce  a  bar  or  casting  of  definite 
strength.  It  is  its  influence  relatively  to  the  mass,  and 


IRON— MELTING  AND  TESTING  43 

not  the  exact  proportion  of  silicon  relatively  to  chemical 
composition,  which  is  the  essential  crux  of  these  methods. 
Irons  of  exactly  the  same  chemical  composition  poured 
from  the  same  ladle  will  not  produce  bars  of  precisely 
the  same  strength.  But  the  shrinkage  of  a  casting,  which 
can  be  controlled  by  silicon,  can  be  measured,  and  the 
shrinkage  determines  the  degree  of  crystallization,  close- 
ness and  uniformity  of  grain  and  texture,  and  therein 
lies  its  value.  The  necessary  amount  to  be  added  de- 
pends not  only  on  the  percentage  quantity  of  carbon 
present,  but  also,  and  much  more,  upon  the  mass  of  the 
casting.  The  addition  of  silicon  retards  cooling  gener- 
ally, producing  the  separation  of  graphite,  and  diminishes 
shrinkage.  The  throwing  out  of  graphite  from  combined 
carbon  removes  brittleness.  If  shrinkage  is  too  great, 
increase  the  silicon,  and  rice  versa.  In  small  bars  and 
castings  the  silicon  must  be  high  (up  to  3  per  cent.),  and 
in  large  bars  and  castings  it  must  be  low.  The  reason 
lies  in  the  difference  in  shrinkage.  A  small  casting 
shrinks  quickly,  and  therefore  needs  more  silicon  to 
throw  out  the  combined  carbon  as  graphite.  A  large 
casting  shrinks  slowly,  and  therefore  requires  less  silicon 
to  effect  the  separation  of  graphite.  Without  the  silicon 
it  is  possible,  and  would  in  fact  occur  in  extreme  cases, 
that  from  the  same  metal  a  small  casting  may  be  white, 
one  of  average  dimensions  mottled,  and  a  very  large  one 
in  the  main  gray. 

The  details  of  the  tests  are  these:  Bars  are  cast  be- 
tween chills  or  yokes  in  order  first  to  ensure  absolute 
uniformity  in  length,  and  to  get  a  chill  on  the  ends. 
The  bars  are  of  two  sizes,  12  x  \  x  \  in.,  and  12  x  1  x  TV  in. 
The  thin  bar  is  used  for  fluidity  test,  because  none  but 
very  fluid  and  hot  iron  will  run  the  whole  length  of 


44  PRACTICAL  IRON  FOUNDING 

the  bar.  The  experience  of  the  moulder  soon  enables 
him  to  judge  of  the  behaviour  of  metal  of  a  given  quality 
in  castings  of  different  dimensions,  made  from  metal 
which  gives  certain  results  in  a  test  bar.  And  in  order 
to  furnish  a  ready  means  of  comparison  between  bars  of 
different  dimensions  Mr.  Keep  has  constructed  an  ideal 
chart  for  ready  reference. 

Great  care  is  taken  to  ensure  uniform  results  in  the 
testing,  metal  patterns  being  used  on  a  bottom  board, 
and  no  rapping  or  touching  up  of  the  mould  is  done. 
The  length  between  the  end  faces  is  12 J  in.  There  are 
four  points  noted — the  amount  of  shrinkage  of  the  bar, 
the  strength  under  dead  load  and  under  impact,  the 
depth  of  chill,  and  the  aspect  of  the  fractured  surfaces. 
The  dead  load  and  impact  tests  are  conducted  in  auto- 
graphic recording  machines.  The  depth  of  chill  is  ascer- 
tained by  fracturing  a  bit  out  of  the  bar  next  the  end. 
The  chill  will  run  from  •£%  to  ^  in.  inwards,  according 
to  quality,  and  is  an  important  element  in  judging  the 
suitability  of  an  iron  for  a  given  purpose.  At  the  same 
time,  the  aspect  of  the  unchilled  fractured  surface  is 
indicative  of  the  open  or  close  nature  of  the  iron. 

Chilling. — When  iron  is  poured  into  metallic  moulds 
instead  of  into  those  of  sand,  the  result  is  that  the  sur- 
face of  the  casting  so  poured  becomes  of  a  steely  char- 
acter, so  extremely  hard  that  no  cutting  tool  will  attack 
it,  and  more  durable,  more  capable  of  resisting  the 
action  of  friction,  than  steel  itself.  It  is  believed  that 
this  chilling,  as  it  is  called,  takes  place  in  consequence 
of  the  combined  carbon  in  the  iron  not  having  time  to 
separate  out  as  graphite.  Poor  irons  will  not  chill 
deeply.  To  produce  chilling  of  £  in.  or  £  in.  in  depth,  the 
metal  must  be  tough,  strong,  and  mottled.  A  strong  iron 


IRON— MELTING  AND  TESTING  45 

is  also  necessary,  because  there  is  tremendous  stress  in  a 
chilled  casting,  owing  to  the  inequality  in  the  shrinkage 
strains  in  the  contiguous  portions,  which  are  rapidly,  or 
slowly  cooled. 

The  iron  for  chilling  should  not  be  poured  very  hot, 
but  dull,  it  will  then  lay  more  quietly  in  the  mould.  The 
chill  should  also  be  heated  in  the  stove  to  so  high  a 
temperature  that  it  cannot  be  touched  with  the  hands. 
To  pour  metal  into  a  cold  chill  is  always  dangerous.  The 
surface  of  the  chill  is  protected  with  a  coat  of  black 
wash  or  other  refractory  material.  In  no  case  should 
the  metal  be  allowed  to  beat  long  against  a  localized 
spot,  as  burning  of  the  chill  and  partial  fusion  of  the 
same  to  the  molten  metal  is  certain  to  ensue.  The  mass 
of  metal  in  a  chill  should  be  large.  The  chill  should 
always  be  much  heavier  than  the  casting  which  has  to 
be  poured  into  it;  without  sufficient  mass,  fracture  is 
almost  certain  to  occur. 

Permanent  moulds. — The  experience  now  being  gained 
with  permanent  moulds  of  metal  promises  economies  in 
some  classes  of  castings.  If  the  ramming  of  a  fresh  sand 
mould  for  every  casting  could  be  abandoned  in  certain 
kinds  of  repetitive  work,  a  great  vista  of  cost-saving 
would  be  in  sight.  It  has  long  been  done  in  chilled 
castings ;  but,  the  chilling  effect  of  a  metal  mould  must 
be  avoided  in  the  general  run  of  castings,  such  as  it  is 
desirable  to  produce  in  permanent  moulds,  and  this 
tendency  to  chill  is  the  principal  difficulty  met  with  in 
casting  in  these  moulds.  The  remedy  is  to  get  the 
casting  out  before  chill  has  formed.  The  time  to  be 
allowed  lies  within  extremely  narrow  limits  for  any  one 
shape  or  mass  of  casting,  but  it  varies  with  different 
shapes  and  sizes.  The  chemical  composition  of  the  iron 


46  PRACTICAL  IRON  FOUNDING 

has  also  some  influence.  The  difference  between  the 
chemical  composition  of  deep-chilling,  and  practically 
non-chilling  irons  is  vital,  whether  the  grading  is  done  by 
fracture  or  by  analysis.  But  the  non-chilling  irons  will 
be  hardened  on  the  surface  if  allowed  to  cool  in  a  metal 
mould,  and  this  hardening  must  be  prevented. 

Castings  left  to  cool  and  chill  in  a  metal  mould  have 
all  their  carbon  in  the  form  of  hard,  needle-like  crystals, 
provided  always  that  the  silicon  is  low.  If  the  same 
castings  are  taken  out  as  soon  as  the  exterior  has  set, 
the  carbon  will  distribute  itself  in  the  graphitic  form 
throughout  the  mass.  This  is  the  reason  why  castings 
are  removed  from  permanent  moulds  immediately  they 
have  set,  and  while  still  at  a  bright  yellow  or  orange  tint. 
An  interesting  fact  is  that  a  large  content  of  phosphorus 
and  sulphur,  sufficient  to  weaken  a  casting  made  in  green 
sand,  has  no  such  result  in  castings  poured  in  permanent 
moulds. 

Attempts  have  been  made,  but  with  little  success,  to 
coat  the  interior  of  the  metal  moulds  when  cold  with 
various  substances  to  prevent  chill — pulverized  talc,  or 
chalk  mixed  with  gasolene  or  kerosene,  and  dried. 
When  moulds  are  hot,  heavy  oils  or  paraffin  have  been 
used.  But  in  the  latest  practice  no  coatings  are  em- 
ployed. 


CHAPTEK  IV 

CUPOLAS,  BLAST,  AND  LADLES 

ALTHOUGH  for  special  purposes  iron  is  sometimes  melted 
on  the  hearth  of  the  reverberatory  furnace,  yet  for  all  the 
usual  run  of  work  the  cupola  furnace  is  that  which  is 
everywhere  employed.  The  best  cupola  furnaces  which 
are  in  use  to-day  differ  from  those  of  half  a  century  ago. 
Better  cupolas  have  been  designed  in  some  respects, 
more  economical  in  fuel,  but  many,  the  older  ones,  are 
retained,  chiefly,  it  must  be  supposed,  by  virtue  of  their 
simplicity,  and  also  because,  in  the  hands  of  a  careful 
furnaceman,  fairly  good  commercial  results  can  be  ob- 
tained therefrom.  Before  noting  some  of  the  improve- 
ments which  have  been  made  in  cupolas,  I  will  briefly 
describe  one  of  ordinary  form  (Figs.  10  and  11),  and  of 
moderate  capacity,  such  as  may  be  seen  in  daily  work  in 
many  foundries. 

The  base  A  is  of  brick,  covered  with  a  cast-iron  plate, 
B.  The  shell  C  is  of  boiler  plate,  single  riveted,  lined 
with  fire-brick,  arranged  as  headers,  set  in  fire-clay. 
In  small  cupolas  there  is  only  one  course  of  bricks,  in 
large  ones  they  are  two  courses  deep.  The  vitrified  slag 
soon  forms  a  glassy  skin  over  the  bricks,  and  thus 
becomes  a  protective  coating  to  them.  A  bed  of  sand,  D, 
is  beaten  hard  down  on  the  bottom,  and  upon  this  is 
placed  the  bed  charge,  E,  of  coke ;  metal,  coke,  and  flux 
alternating  thence  all  the  way  up  to  the  charging  door, 

47 


FIG.  10, — CUPOLA,   ELEVATION, 


CUPOLAS,  BLAST,  AND  LADLES 


49 


F,  which  is  about  a  couple  of  feet  above  the  charging 
platform,  L  The  blast  necessary  for  combustion  is 
brought  in  at  the  two  tuyere  pipes,  G,  G,  from  the  blast 
main,  H,  which  is  properly  placed  below  the  ground,  as 


I:  iv-iot 


SECTION  N— N 
FIG.  11.— CUPOLA.    SECTIONS. 

shown.  The  metal  is  tapped  out  at  the  hole,  J,  (Fig.  11), 
the  spout  of  which,  K,  is  usually  brought  through  the 
foundry  wall,  outside  of  which  the  cupola  is  properly 
placed.  L  is  the  door  closing  the  breast  hole,  through 
which  the  fire  is  lit,  which  is  closed  just  previous  to 
the  turning  on  of  the  blast,  and  through  which  the 


50  PRACTICAL  IRON  FOUNDING 

embers  are  raked  after  the  casting  is  done.  Above  the 
breast  hole  is  the  slag  hole,  M,  placed  just  below  the 
level  of  the  tuyere  openings.  Through  this  the  slag 
is  tapped  out  at  intervals  during  the  process  of 
melting. 

Charging. — The  method  of  charging  is  as  follows.  First 
of  all,  the  interior  up  to  the  height  of  the  tuyere  holes 
is  lined  for  a  thickness  of  £  in.  or  1  in.  with  fire-clay,  or 
with  loamy  sand.  The  tap  hole,  J,  is  lined  by  ramming 
sand  and  fire-clay  around  a  pointed  bar  inserted  in  the 
opening  in  the  bricks.  A  fire  is  lit  in  the  bottom,  and  a 
bed  charge,  E,  of  coke  is  laid  upon  this.  Then  follows  a 
charge  of  iron  and  flux,  and  again  a  layer  of  coke,  and 
so  on  alternately,  as  seen  in  Fig.  10.  This  is  done  two 
or  three  hours  before  the  blast  is  put  on,  and  in  the 
meantime  the  various  openings  into  the  cupola  remain- 
ing open,  the  fuel  burns  up  quietly,  and  everything  be- 
comes warmed  equably  throughout.  When  the  time 
arrives  for  the  melting  down  of  the  metal,  the  breast- 
plate, L,  is  lined  with  sand,  and  wedged  in  place,  the 
tuyere  pipes,  G,  the  bends  of  which  are  made  to  swivel,  are 
put  into  position  and  luted  with  clay,  and  the  tap  hole,  J, 
being  open,  a  gentle  blast  is  put  on  for  five  or  ten  min- 
utes. This  has  the  effect  of  hardening  the  clay  in  the 
tap  hole.  The  blast  is  then  stopped,  the  tap  hole  closed 
with  clay  by  means  of  the  bot-stick,  and  the  full  blast 
pressure  is  put  on.  In  from  ten  to  fifteen  minutes  the 
metal  begins  to  run  down,  and  presently,  when  the  fur- 
naceman  observes  through  the  mica  sight  holes,  H',  H', 
of  the  tuyeres  that  the  metal  is  getting  nearly  to  the 
level  of  the  tuyere  openings,  he  taps  out  a  quantity  into 
a  ladle.  This  is  done  by  driving  the  pointed  end  of  the 
bot-stick  through  the  hard-baked  clay,  giving  the  stick 


CUPOLAS,  BLAST,  AND  LADLES  51 

a  rotary  motion  with  his  hands,  to  enlarge  the  hole.  The 
metal  then  runs  down  the  shoot,  K,  in  a  steady  stream, 
and  when  the  ladle  is  nearly  filled,  the  tap  hole  is  closed 
with  a  daub  of  clay  held  on  the  flat  end  of  a  bot-stick, 
the  stick  being  held  diagonally  downwards  towards  the 
hole  at  first,  and  then  lowered  sharply  until  the  axis  of 
the  stick  is  in  line  with  the  hole  J,  so  closing  it  up  with- 
out risk  of  spluttering  of  the  iron. 

As  the  metal  runs  down,  additional  quantities  of  iron, 
fuel,  and  flux  are  charged  in  at  the  door,  F.  Slag  forms 
in  quantity,  and  this  has  to  be  tapped  out  at  intervals 
through  the  slagging  hole,  M.  The  slagging  will  have  to 
be  repeated  more  or  less  often  according  to  the  inferior, 
or  superior  class  of  the  metal.  As  long  as  slag  continues 
to  run,  the  hole  should  be  left  open.  If  very  inferior  or 
burnt  iron  is  being  melted  the  slag  may  be  running 
nearly  all  the  while.  The  economy  of  cupola  practice  is 
largely  dependent  on  keeping  the  surface  of  the  metal 
free  from  slag. 

Charges  of  metal  of  different  kinds  are  melted  in  the 
cupola  at  the  same  time,  by  interposing  between  each 
charge  a  stratum  of  coke  rather  thicker  than  those  used 
in  the  ordinary  work  of  melting.  The  charge  which  is 
lowermost  is  then  tapped  out,  as  the  charge  above  begins 
to  melt,  and  the  furnaceman  is  able  to  see  the  beginning 
of  the  melting  of  an  upper  charge  at  the  sight  holes,  II',  1L'. 

Large  quantities  of  metal  are  tapped  out  in  detail,  a 
ton  or  a  couple  of  tons  at  a  time,  until  sufficient  has 
accumulated  in  the  ladle.  Metal  in  the  ladle  will  retain 
its  heat  for  a  very  long  time  if  radiation  is  prevented  by 
sprinkling  the  surface  with  the  blowings  from  a  smith's 
forge,  and  by  allowing  the  oxide  and  scum  to  remain 
thereon. 


52  PRACTICAL  IRON  FOUNDING 

When  the  melting  down  is  done,  the  whole  of  the  fur- 
nace contents  are  raked  out  through  the  breast  hole,  or, 
if  the  cupola  is  of  the  drop  bottom  type,  like  Fig.  12, 
p.  55,  by  dropping  the  bottom.  Under  no  circumstances 
can  the  metal  and  fuel  remain  safely  in  a  cupola  long 
after  the  blast  is  shut  off,  since,  if  it  sets,  the  mass  will 
bung  up  or  gob  up  the  furnace,  forming  a  salamander,  and 
the  furnace  lining  may  probably  be  destroyed  in  the  re- 
moval of  the  obstruction. 

Economical  melting. — The  proper  melting  of  metal  is  a 
task  requiring  a  good  deal  of  experience  and  caution. 
Economical  melting  is  an  excellent  thing,  but  there  are 
other  points  which  have  to  be  regarded  besides  the  state- 
ment on  paper  that  a  ton  of  metal  has  been  melted  with 
a  certain  percentage  of  fuel.  Iron  may  be  melted  so  dull 
that  poor,  if  not  waster  castings  result,  when  a  little  more 
fuel  would  have  dead-melted  it  thoroughly,  producing 
good,  sound,  homogeneous  castings.  Then  the  size  of  the 
cupola,  and  the  amount  of  work  being  done,  has  to  be 
taken  into  account.  A  small  cupola  is  more  wasteful  in 
fuel  than  a  large  one.  A  cupola  running  two  or  three 
hours  daily  is  more  wasteful  than  one  running  all  the 
day.  Inferior  iron  is  more  wasteful  of  fuel  than  iron  of 
superior  quality.  Hence  general  porportions  only  can  be 
given  for  percentages  of  fuel.  The  total  percentage  of 
fuel  to  iron  melted  may  range  economically  from  1-J-  cwt. 
to  3  cwt.  per  ton,  according  to  circumstances.  Total 
percentage  includes  the  fuel  used  in  the  bed  charge. 
This  always  bears  a  large  proportion  to  the  total  amount 
used,  hence  the  reason  why  short  meltings  are  so  much 
more  costly  than  lengthy  casts.  For  a  cupola  like  Fig.  10, 
4  ft.  diameter,  a  bed  charge,  E,  of  1(H  cwt.  is  used;  for 
a  similar  cupola,  2  it.  4  in.  in  diameter,  a  bed  charge  of 


CUPOLAS,  BLAST,  AND  LADLES  53 

6  cwt.  is  used.  But  the  bed  charge  will  equal  about  one 
half  the  quantity  of  coke  required  for  a  "  blow "  of 
moderate  length,  say  of  from  two  or  three  hours. 

The  succession  of  charges  in  the  cupolas  of  the  two 
sizes  above-named  is  as  follows:  4ft.  cupola:  bed  charge 
10-J-  cwt.;  each  charge  of  iron  21  cwt.,  separated  by 
2|-  cwt.  of  coke;  }  cwt.  of  limestone  (flux)  in  bed  charge, 
and  seven  or  eight  pounds  on  each  subsequent  charge. 
2  ft.  4  in.  cupola:  6  cwt.  bed  charge,  each  charge  of  iron 
14  cwt.,  1|  cwt.  of  coke  in  each  subsequent  charge.  The 
first  cupola  will  melt  four  tons  per  hour,  the  second  from 
two  and  half  to  three  tons  per  hour.  But  in  the  first 
cupola,  with  heavy  casts,  twelve  tons  can  be  melted  with 
twenty-five  cwt.  of  coke,  including  bed  charges. 

In  cupolas  such  as  these,  doing  jobbing  work,  using 
different  mixtures  of  iron,  making  many  light  casts,  and 
running  from  two  to  four  hours  per  day,  the  conditions 
for  economy  of  fuel  do  not  exist,  and  as  much  as  two  cwt. 
of  fuel  per  ton  of  metal  melted  will  not  be  an  unreason- 
able proportion.  Where  contrary  conditions  exist,  the 
proportions  may  be  less  by  nearly  one  half. 

The  chemical  conditions  which  govern  economical 
working  are  those  which  relate  to  the  purity  of  the  fuel, 
and  to  the  complete  utilization  of  the  products  of  com- 
bustion. The  coke  should  be  the  best  and  purest  pro- 
curable, free  from  sulphur,  hard,  columnar,  heavy,  having 
metallic  lustre,  and  clean.  The  height  of  a  cupola,  the 
position  and  number  of  tuyeres,  the  density  of  the  blast, 
all  vitally  influence  the  ultimate  results.  Height  is  ne- 
cessary, because  without  it  large  quantities  of  combustible 
gas  would  escape  unburnt  and  become  lost. 

Combustion. — The  process  of  combustion  is  as  follows: 
Air,  under  pressure,  entering  the  cupola  through  the 


54  PRACTICAL  IRON  FOUNDING 

tuyeres,  meets  with  the  heated  fuel.  The  oxygen  in  the  air 
combines  with  the  incandescent  carbon  in  the  fuel,  form- 
ing carbonic  anhydride,  C02,  a  gas  which  will  not  burn. 
This  gas  takes  up  more  carbon,  becoming  carbonic  oxide, 
CO,  equivalent  to  C2  02,  which  is  combustible.  If,  however, 
this  gas  does  not  meet  with  sufficient  free  oxygen  at  a 
high  temperature,  it  cannot  burn,  but  will  pass  away, 
representing  a  certain  number  of  heat  units  wasted.  But 
if  it  meets  with  a  sufficiency  of  heated  oxygen  higher  up 
in  the  furnace,  it  burns,  giving  out  heat  available  for 
combustion.  Hence  the  reason  why  the  taller  cupolas 
are  more  economical  than  the  lower  ones.  Flame  at,  and 
above,  the  charging  door  represents  heat  lost,  as  far  as 
useful  work  is  concerned.  Hence  also  the  reason  why 
two  or  three  rows  of  tuyeres,  to  supply  the  zones  of  oxygen 
necessary  for  combustion,  have  been  adopted  in  nearly 
all  cupolas  which  have  been  designed  to  supersede  the 
older  forms,  a  mode  of  construction  which  is  therefore 
seen  to  be  quite  correct  in  principle. 

The  perfect  combustion  of  carbon  to  C02  evolves 
14,647  British  thermal  units  per  pound  of  fuel.  If  only 
partially  burned  to  CO,  only  4,415  British  thermal  units 
are  developed  from  each  pound  of  carbon.  A  pound  of 
carbon  requires  1.33  Ib.  of  oxygen  in  burning  to  CO, 
and  2.66  Ib.  in  burning  to  C02.  If  the  air  supply  is  in- 
sufficient, the  first  oxide  only  is  formed,  and  hardly  a 
third  of  the  heat  possible  is  obtained.  In  other  words, 
more  than  two  thirds  of  the  possible  heat  units  are  lost 
at  the  top  of  the  cupola. 

Even  in  the  highest  melting  ratios  which  are  obtained 
in  practice  the  waste  is  excessive  by  comparison  with  the 
theoretical  values.  Even  though  the  gases  are  burnt 
almost  thoroughly  there  is  much  loss  of  heat  in  warming 


CUPOLAS,  BLAST,  AND  LADLES 


55 


up  the  inert  nitrogen,  in  warming  the  blast,  in  radiation 
of  heat,  and  unavoidable  heat  losses  in  the  iron  and  in 
the  chimney.  Actually  a  ratio  of  10  to  1 
is  very  good;  8  to  1  is  good;  6  or  7  to  1 
represents  satisfactory  practice. 

The  rapid  cupola. — The  embodiment 
of  this  principle  is  illustrated  by  the 
Rapid  cupola,  by  Thwaites  Bros.,  Ltd., 
shown  by  Figs.  12  and  13.  In  this  there 
are  three  zones  of  tuyeres  enclosed  by 
an  air  belt,  and  each  zone  of  tuyeres  can 
be  opened  and  closed  independently  of 
the  others  by  means  of  shut-off  valves. 
The  air  belt,  the  zones  of  tuyeres,  and 
the  boshes  or  sloping  sides,  are,  however, 
of  older  date  than  this  particular  ex- 
ample. Ireland's  cupolas,  much  used  a 
few  years  since,  were  very  tall,  and  were 
IT-J-^  6j  :  provided  with  boshes  or  sloping  sides 

!/8  \  £•'  similarly  to  blast  furnaces,  by  which  the 


Fio.  12.— THE  "RAPID" 
CUPOLA. 


FIG.  13. — PLAN  OF  CUPOLA 
THROUGH  TUYERES. 


weight  of  the  charge  was  sustained.  They,  or  at  least 
the  earlier  ones,  had  two  rows  of  tuyeres,  but  the  upper 
row  was  abandoned  in  later  structures.  Voison's  cupolas 


56  PRACTICAL  IRON  FOUNDING 

were  made  also  with  air  belts  and  with  two  rows  of 
tuyeres.  Numbers  of  common  cupolas,  both  in  this 
country  and  in  America,  have  the  same  arrangement. 
Cupolas  have  been  made  with  shifting  tuyeres,  so  that  in 
the  absence  of  an  air  belt  the  tuyere  pipes  can  be 
moved  to  the  zone  above  or  below  as  required. 

The  other  features  of  the  cupola  are,  a  brick-lined 
receiver  for  the  melted  metal,  by  which  means  the  heat 
is  retained  and  oxidation  prevented,  while  the  blast  pres- 
sure maintains  its  surface  in  agitation,  conducing  to 
proper  mixture  and  homogeneity.  The  waste  heat  there- 
from is  also  utilized  by  passing  up  a  ganister-lined  pipe 
into  the  cupola,  entering  just  above  the  air  belt.  The 
escape  of  the  waste  gases  is  regulated  by  a  flap  door  at 
the  side  of  the  hooded  top. 

The  efficiency  of  this  cupola  ranks  high,  and  it  has 
given  much  satisfaction  where  it  has  been  erected.  In 
blows  of  ordinary  length  it  is  capable  of  melting  one  ton 
of  iron  with  from  one,  to  one  and  a  quarter  hundred- 
weight of  coke.  Particulars  of  dimensions  are  given  in 
the  Appendix. 

The  remarkable  success  of  the  air-belt  design  of 
cupola  is  due  to  the  thoroughness  with  which  theory  has 
been  translated  into  practice.  It  is  based  on  the  fact 
that  there  is  no  free  oxygen  above  the  tuyeres.  Hence 
when  the  blast  enters,  its  oxygen  combines  with  the 
carbon  in  the  fuel  to  form  C02.  This,  in  its  ascent 
through  the  coke,  unites  with  another  atom  of  carbon, 
forming  CO.  This  again  demands  oxygen  for  its  con- 
version into  C02,  with  development  of  intense  heat  of 
combustion. 

In  other  words,  the  conversion  of  as  much  as  possible 
of  the  carbon  in  the  fuel  into  C02  within  the  melting 


CUPOLAS,  BLAST,  AND  LADLES      57 

zone  is  the  object  sought  in  order  to  develop  all  the 
heat  units  possible.  The  arrangement  of  supplementary 
tuyeres,  of  which  there  are  usually  half  a  dozen,  sup- 
plies air  in  small  volumes  to  the  CO  formed  in  the  melt- 
ing zone. 

Tuyeres. — In  arranging  rows  of  tuyeres,  diffusion  and 
not  concentration  of  blast  must  be  accomplished,  and  to 
secure  this  the  openings  should  not  be  arranged  per- 
pendicularly, nor  be  very  far  apart  vertically.  If  they 


FIG.  14. — TUYERES  OF  NEWTEN  CUPOLA. 

supply  a  uniform  and  sufficient  quantity  of  air  to  the 
melting  zone,  which  can  be  judged  by  the  working  of  the 
cupola  in  economy  of  time  and  in  hot  metal,  though  not 
necessarily  in  fuel  consumption,  their  real  efficiency  is 
demonstrated. 

The  Newten  cupola,  Fig.  14,  made  by  the  Northern 
Engineering  Works,  of  Detroit,  Mich.,  has  its  lower  tuyeres 
fitted  with  a  differential  device,  the  object  of  which  is  to 
send  a  portion  of  the  blast  right  to  the  centre,  while  the 
larger  volume  is  diffused  more  softly  about  the  other 


58  PRACTICAL  IRON  FOUNDING 

parts  of  the  cupola.  The  tuyeres  are  of  the  enlarged 
form,  giving  nearly  a  continuous  circle  of  blast;  but  near 
the  centre  of  each,  two  plates  are  set  to  converge,  en- 
closing the  shape  of  a  truncated  cone  through  which  the 
blast,  being  contracted,  is  forced  to  the  centre  of  the 
cupola.  The  remainder  of  the  blast  is  diffused  more 
softly  to  right  and  left. 

Fig.  15  is  a  plan  of  the  tuyere  arrangements  of  the 
Whiting  cupola,  with  a  section  through  the  wind-box. 


FIG.  15. — TUYERES  OP  WHITING  CUPOLA. 

This  shows  in  half  plan  the  upper  and  the  lower  tuyeres, 
alternated  or  staggered  in  relation  to  each  other.  They 
are  flared,  being  nearly  double  the  width  of  opening  at 
the  inside  than  where  they  meet  the  belt.  The  position 
of  the  upper  row  is  fixed,  but  the  lower  row  may  be 
adjusted  to  different  heights.  And  when  desired,  the 
upper  row  may  be  closed  with  dampers  if  the  amount  of 
blast  has  to  be  lessened. 

Melting  ratio. — Various  miscellaneous  arrangements 
of  relatively  minor  importance  contribute  to  the  economy 
or  durability,  or  facilitate  the  working  of  the  cupola ., 


CUPOLAS,  BLAST,  AND  LADLES      59 

The  ultimate  object  is  to  melt  as  much  metal  as  possible 
with  the  smallest  expenditure  of  fuel,  consistently,  of 
course,  with  thorough  melting.  A  certain  quantity  of 
metal,  say  a  ton,  is  melted  by  so  many  hundredweights 
of  coke,  say  two,  three,  or  four.  The  first  divided  by  the 
last  gives  the  "  melting  ratio,"  a  quantity  around  which 
foundry  managers  are  in  rivalry,  and  concerning  which 
no  statement  can  be  made  which  shall  be  of  more  than 
very  general  application. 

The  melting  ratio  must  obviously  be  variable  within 
wide  limits,  because  it  is  under  the  control  of  so  many 
conditions.  Hence  comparisons  and  statements  can  be 
of  real  value  only  if  they  are  made  under  identical  cir- 
cumstances. Sometimes  the  ratio  is  stated  without  in- 
cluding the  amount  of  coke  in  the  bed  charge,  which,  if 
included  in  the  case  of  a  melting  of  short  duration, 
might  reduce  the  ratio  by  nearly  or  quite  one  half.  In  a 
prolonged  melting,  running  down  a  large  quantity  of 
metal,  the  bed  charge  will  form  but  an  insignificant  pro- 
portion to  the  whole. 

Again,  in  casting  light  work,  the  metal  must  neces- 
sarily be  hotter,  that  is,  more  thoroughly  melted,  than 
for  very  massive  work,  and  this  requires  a  larger  propor- 
tion of  fuel;  besides,  a  pure  clean  pig  and  scrap  will  re- 
quire less  fuel  to  melt  thoroughly  than  a  lot  of  dirty 
inferior  scrap,  with  much  slag,  will  want.  But  even 
observing  these  differences,  and  including  the  bed 
charge,  in  all  comparisons  there  is  much  difference  in 
cupola  performances,  greatly  to  the  disadvantage  of  the 
older  types. 

Drop  bottom. — The  hinged  drop  bottom,  though  not 
in  any  way  related  to  the  efficiency  of  a  cupola,  is  much 
to  be  preferred  to  the  older  solid  bottom.  The  hinged 


60  PRACTICAL  IRON  FOUNDING 

door,  on  being  released  by  a  latch,  allows  all  the  con- 
tents to  fall  out  at  once.  With  a  solid  bottom  they  have 
to  be  raked  out  at  the  side,  an  operation  which  occupies 
ten  or  fifteen  minutes,  and  is  very  hot  work.  It  is  neces- 
sary also  to  melt  all  the  superfluous  metal  in  order  to 
run  it  out  from  a  solid  bottom,  while  it  can  be  dis- 
charged from  a  drop  bottom  unmelted  or  partly  melted, 
along  with  the  partly  burnt  coke  and  slag.  If  water  is 
thrown  over  it,  the  constituents  can  be  separated  and 
used  again  next  day. 

Blast. — The  proper  pressure  of  blast  is  a  matter  of 
great  importance.  A  soft  blast  will  not  melt  the  metal 
quickly  nor  thoroughly,  and  will  cause  wasteful  ex- 
penditure of  fuel.  A  sharp  blast  will  blow  away  the  fuel 
before  perfect  combustion  ensues.  Cupolas  of  large 
capacity  have  been  made  elliptical  in  plan  instead  of 
circular,  to  enable  the  blast  to  penetrate  better  to  the 
interior. 

It  is  difficult  to  put  in  figures  any  rules  for  the  blast 
pressure  of  cupolas,  since  it  by  no  means  follows  that 
the  pressure  in  a  cupola  is  the  same  as  that  in  the  blast 
pipes;  it  is  really  less — very  much  less — if  the  pipes  are 
not  selected  of  suitable  size,  and  laid  properly;  and  it  is 
further  very  variable,  depending  on  the  condition  in 
which  the  furnaceman  keeps  the  cupola,  the  presence  of 
slag,  dirt,  and  partially  choked  tuyeres,  and  too  close 
charging,  so  diminishing  blast  pressure.  The  pressure 
in  a  cupola  varies  within  several  ounces  from  the  time 
of  putting  on  the  blast  to  the  period  of  full  melting.  The 
differences  are  due  to  the  increase  of  resistance  of  the 
molten  iron  and  slag,  preventing  that  ready  escape  of 
the  air  which  occurs  through  interstices  of  the  fuel  and 
unmelted  iron.  A  gauge  supplies  the  means  for  reading 


CUPOLAS,  BLAST,  AND  LADLES      61 

these  variations  of  pressure.  It  is  graduated  to  ounces, 
and  reads  to  2  Ib.  No  cupola  should  be  without  one  of 
these  specially-constructed  blast  pressure  gauges,  in 
which  the  pressure  or  density  is  measured  in  inches  of 
water.  An  inch  of  water  gives  a  pressure  of  0.5773  oz. 
per  square  inch.  Blast  pressure  may  range  from  5  oz.  or 
6  oz.  to  18  oz.  Say  we  have,  as  an  example,  a  pressure  of 
12  oz.,  that  would  be  equivalent  to  6.9276  in.  of  water, 
or  0.88  in.  of  mercury,  and  this  may  be  taken  as  a  rough 
average  approximation  to  ordinary  cupola  blast  pressure ; 
or,  putting  it  in  round  numbers,  7  in.  or  8  in.  of  water, 
and  1  in.  of  mercury.  The  larger  the  furnace,  the  higher, 
of  course,  the  pressure  required. 

Fans  and  blowers. — For  the  production  of  blast,  fans 
and  blowers  are  employed,  by  which  the  air  enters  the 
cupola  under  pressure.  There  is  no  virtue  in  mere  press- 
ure as  such,  but  a  certain  rapidity  of  combustion  is 
necessary  in  order  to  the  efficient  melting  of  metal. 
The  pressure  is  not  great,  seldom  more  than  12  oz.  per 
square  inch,  but  at  such  a  pressure  an  enormous  volume 
of  air  passes  through  the  tuyeres  in  the  course  of  a  min- 
ute. 30,000  to  40,000  cubic  feet  of  air  is  necessary  to 
melt  a  ton  of  iron,  and  from  20,000  to  30,000  cubic  feet 
is  necessary  to  consume  1  cwt.  of  coke.  The  volume  of 
air  is  necessarily  large,  since,  of  the  oxygen,  much  is  lost 
through  imperfect  combustion,  and  the  nitrogen  is  inert. 

The  difference  between  a  fan  and  a  blower  is,  that  the 
fan  acts  by  inducing  a  current  of  air,  the  blower  produces 
a  positive  pressure.  The  fan  therefore  has  to  revolve  at 
a  very  high  rate  of  speed,  causing  an  attendant  train  of 
evils  inseparable  from  high  speeds;  the  blower  need  only 
revolve  at  a  very  moderate  rate.  The  pressure  and  volume 
are  under  greater  control  with  a  blower  than  with  a  fan. 


62 


PRACTICAL  IRON  FOUNDING 


The  common  fan  consists  of  an  outer  casing,  cast  in 
halves,  and  bolted  together.  Within  it  revolve  the 
blades,  or  vanes,  upon  a  spindle  which  runs  in  long 
bearings,  and  which  is  driven  by  belt  pulleys.  The 


FIGS.  1(J  AND  17. — TYPES  OF  BLOWEKS. 

revolution  of  the  vanes  produces  a  partial  vacuum  within 
the  casing,  into  which  air  rushes  from  openings  at  the 
sides  of  the  casing,  gathering  momentum,  like  a  falling 
body,  with  increase  of  speed,  and  is  forced  out  through 
the  nozzle  of  the  casing  into  the  blast  main. 

In  the  blower  (Figs.  16  and  17),  the  air  which  enters 


CUPOLAS,  BLAST,  AND  LADLES      63 

the  casing  (from  below  in  the  figures)  is  forced  forward 
under  constant  pressure  by  the  revolving  pistons  or 
impellers  into  the  outlet  above,  which  communicates 
with  the  blast  main.  These  impellers  are  of  cast  iron, 
shaped  to  templet,  and  fit  so  accurately  into  each  other, 
and  to  the  bored  casing,  that  the  thickness  of  a  sheet  of 
paper  alone  preserves  them  from  actual  contact.  The 
narrow,  almost  pointed  ends  serve  to  sweep  out  any 
deposit  of  dirt  or  grit  which  may  enter  within  the  casing. 
Being  lubricated  with  a  very  thin  coating  of  red  oxide 
paint,  they  run,  though  practically  air-tight,  with  the 
very  minimum  of  friction.  Two  examples  of  Boots' 
blowers  are  shown  by  Fig.  18,  Plate  I,  and  Fig.  19, 
Plate  II,  the  first  being  geared  direct  to  an  electric  motor, 
the  second  driven  by  the  special  type  of  engine  which  is 
used  for  these,  with  two  connecting  rods.  Ordinary  high- 
speed enclosed  type  engines  are  also  employed  tor  this 
function,  with  a  heavy  flywheel  on  the  shaft,  and  con- 
nection to  the  second  shaft  by  the  usual  gears.  These 
are  by  Thwaites  Bros.,  Ltd.,  of  Bradford,  Yorkshire.  A 
table  of  the  performances  and  other  particulars  of  Boots' 
blowers  is  given  in  the  Appendix. 

In  Baker's  blower  there  are  three  revolvers  or  drams, 
each  of  circular  section.  Two  of  these  are  slotted  through- 
out their  entire  length  in  order  to  allow  the  pair  of 
radial  wings  in  the  upper  drum  which  propels  the  air  to 
clear  inside  them.  The  lower  drums  are  so  arranged 
that  contact  is  never  broken  between  one  or  other  of 
them  and  the  upper  drum.  The  upper  drum  is  furnished 
with  two  radial  arms  which  alternately  sweep  through 
the  hollow  portions  of  the  two  drums  placed  beneath  it 
In  this  case  also  the  casing  is  bored  out  truly  to  prevent 
escape  of  air  and  to  ensure  smooth  working. 


64  PRACTICAL  IRON  FOUNDING 

Controversy  respecting  the  relative  merits  of  fans  and 
blowers  is  perennial.  Each  has  its  advocates,  but  an  un- 
biassed mind  will  admit  that  between  the  best  of  each 
there  is  little  if  anything  to  choose.  The  points  in  favour 
of  each  are  these. 

With  the  blower,  practically  the  same  volume  of  air 
which  is  drawn  in  must  be  forced  out,  for  a  well  made 
machine  should  have  no  perceptible  leakage.  Hence  the 
volume  of  air  can  be  controlled  exactly  by  varying  the 
number  of  revolutions  of  the  blower,  an  increase  in  which 
increases  the  melting  capacity  of  a  cupola.  The  volume 
of  air  supplied  being  uniform  under  similar  conditions 
the  pressure  increases  with  resistance  offered,  so  that  a 
blower  will  force  air  through  slag  obstructions,  or  through 
charges  of  increasing  density.  So  that  pressure  may  rise 
from  8  oz.  to  1(>  oz.  in  the  course  of  a  blow.  This  is  all 
in  favour  of  the  blower.  Moreover,  very  minute  fluctua- 
tions occur  in  pressure  during  each  revolution,  occurring 
each  time  the  arm  of  an  impeller  discharges  air.  This  is 
also  claimed  as  of  value  in  regular  melting. 

The  fan  acts  by  imparting  momentum  to  the  air  and 
not  by  displacing  a  precise  volume  equal  to  the  cubic 
capacity  of  the  blower.  The  term  centrifugal  denotes  that 
the  air  is  delivered  by  centrifugal  force  at  the  circum- 
ference. The  rotation  produces  a  partial  vacuum  about 
the  centre,  to  occupy  which  air  enters  at  the  openings  in 
the  sides.  Pressure  is  increased  with  increase  in  the 
rapidity  of  the  revolutions,  and  in  the  ratio  of  the  square 
of  the  speed.  The  speed  of  a  fan  cannot  be  increased 
beyond  the  proper  speed  for  which  it  is  rated  without 
absorbing  additional  power  in  the  ratio  of  the  cube  of  the 
number  of  revolutions.  So  that  a  fan  will,  under  these 
circumstances,  be  a  wasteful  machine.  Actually  fans 


PLATE  II 


9 


Seep.  63  \Fatingp.M 

FIG.  19.— ROOTS'  BLOWER,  DRIVEN  BY  SELF-CONTAINED 
STEAM  ENGINE 


CUPOLAS,  BLAST,  AND  LADLES  65 

should  be  selected  of  capacities  large  enough  for  their 
work,  and  for  this  the  tables  of  manufacturers  may  be 
accepted  as  a  working  basis.  And  further,  the  pipe 
arrangements  must  be  free,  large,  short  in  length,  and 
without  any  quick  bends,  if  the  fan  pressure  is  to  be 
maintained  at  the  cupola.  The  fan  is  not  so  well  able 
to  force  air  through  dense  charges  of  slag  as  the  blower 
is.  On  the  other  hand  it  produces  a  softer  blast.  It  is 
desirable  with  fans  to  have  a  blast  gate  in  the  main  pipe 
for  regulating  the  supply  as  the  demands  made  upon  it 
vary.  The  elasticity  or  flexibility  of  the  fan,  its  self- 
adjusting  capacity,  is  in  its  favour  in  the  opinion  of  many 
foundrymen.  But  unless  a  fan  is  selected  fully  large 
enough  for  its  work  and  run  at  suitable  speeds,  it  will 
prove  very  inefficient.  In  its  favour  is  that  of  costing- 
less  than  the  blower,  requiring  less  solid  foundations, 
and  being  less  expensive  for  repairs. 

The  attempt  has  been  made  to  employ  a  jet  of  steam 
to  induce  the  blast  current.  This  was  the  peculiarity  of 
Woodward's  cupola. 

In  the  Herbertz  cupola  also  the  blast  is  induced  by  an 
exhausting  jet  of  steam.  The  jet  operates  in  a  flue  near 
the  charging  door,  and  the  blast  enters  through  an  annu- 
lar opening  immediately  above  the  hearth.  The  width 
of  this  opening  is  capable  of  adjustment  by  means  of 
screws  for  the  production  of  a  cutting  or  of  a  soft  blast. 

Ladles. — For  the  pouring  of  metal  into  moulds,  ladles 
of  various  kinds  are  employed.  The  ordinary  forms  are 
shown  in  the  accompanying  illustrations.  In  the  group  of 
Fig.  20,  Plate  III,  the  smallest,  the  second  from  the  top, 
is  a  hand  ladle  holding  a  half  hundredweight  only,  used 
for  very  light  casts  and  supplying  feeder  heads  with  hot 
metal.  Above  it  is  seen  the  double  handled  shank  ladle, 

F 


66  PRACTICAL  IRON  FOUNDING 

made  in  capacities  ranging  from  one  to  about  four  hun- 
dredweights: two,  three,  or  four  men  carry  these  ladles, 
according  to  the  weight.  Thus  there  may  be  one,  or  two 
men  at  the  cross  handle;  and  one,  or  two  at  the  straight 
shank.  When  made  for  two,  the  end  of  the  shank  is 


FIG.  21. — DOUBLE-GEARED  LADLE. 

turned  down,  and  is  supported  on  a  cross  bar,  each  end  of 
which  is  held  by  a  labourer.  The  third  down  in  the  group 
is  a  heavier,  or  crane  ladle;  it  may  range  from  ten  hun- 
dredweights to  a  ton  in  capacity.  It  is  slung  in  the  crane 
hook;  the  catch  seen  on  the  right  prevents  the  ladle  from 
becoming  accidentally  up-tipped,  and,  when  thrown  back, 
a  man  standing  at  the  cross  handle  turns  the  metal  into 


CUPOLAS,  BLAST,  AND  LADLES 


67 


the  mould.  The  heaviest  ladles  are  of  the  type  shown 
below.  These  are  geared  ladles,  which  may  range  from 
one  to  twelve  tons  in  capacity.  The  geared  ladle  was  the 


FIG.  22. — DOUBLE-GEARED  LADLE. 


invention  of  Mr.  Nasmyth,  and  a  graphic  illus- 
tration of  the  contrast  between  it  and  the  old  ungeared 
form  is  given  in  his  admirable  autobiography.  The  ladle 
in  the  Fig.  is  double  geared,  having  mitre  wheels  in 


68  PRACTICAL  IRON  FOUNDING 

addition  to  the  worm  gear.  Many  ladles  have  the  latter 
only.  A  weight  of  several  tons  is  tipped  easily  and 
steadily  into  the  mould  by  means  of  the  geared  ladles. 


FIG.  26. — GOODWIN  AND  How's  PATENT  LADLE. 

Figs.  21  and  22  show  the  construction  of  a  double- 
geared  ladle  by  Charles  McNeil,  of  Glasgow,  of  25  cwt. 
capacity.  The  worm  gear  for  tipping  is  turned  by  the 
application  of  the  handle  either  directly  on  the  square 


CUPOLAS,  BLAST,  AND  LADLES      69 

on  the  worm  shaft,  or  if  more  convenient  at  right  angles 
on  the  square  of  the  mitre  gear  shaft.  Fig.  23,  Plate  IV, 
represents  a  worm-geared  ladle  of  12  tons  capacity,  by 


FIG.  27. — GOODWIN  AND  How's  PATENT  LADLE. 

Messrs.  Thwaites  Bros.,  Ltd.,  with  riveted  body,  and 
Fig.  24  is  a  10  cwt.  ungeared  ladle  mounted  on  a  four- 
wheel  bogie.  A  heavier  class  of  ladle — 5  tons  capacity — 
Fig.  25,  Plate  IV,  is  provided  with  a  lifting  bar  so  that 
it  may  be  lifted  on  and  off  by  the  crane.  The  eight- 


70  PRACTICAL  IRON  FOUNDING 

wheel  bogie  carriage  has  ball-bearing  swivels,  and  the 
wheels  are  flanged  to  run  on  a  track.  These  ladles  are, 
except  the  smallest,  which  are  of  cast  iron,  made  of  steel 
plate  riveted  together.  The  McNeil  ladles  are  of  pressed 
steel. 

Ladles  are  daubed  every  morning  before  casting  with 
fire-clay,  or  loamy  sand,  and  blackwashed.  This  lining 
is  dried,  in  the  case  of  the  smaller  ladles,  over  a  coke 
fire,  in  the  larger  ones  by  lighting  a  fire  of  wood  within 
them.  After  casting,  the  skulls  are  chipped  out  with  a 
hand  hammer. 

Skimmimg. — When  metal  is  poured  from  a  ladle,  a  boy 
holds  a  rectangular  bar  of  iron  across  the  mouth,  to  bay 
back  the  scoriae  which  floats  on  the  surface,  so  prevent- 
ing it  from  entering  the  mould,  to  the  detriment  of  the 
casting.  The  method  is  necessarily  an  unsatisfactory  one, 
but  few  attempts  have  been  made  to  remedy  it.  Two 
forms  of  ladles  have  been  patented,  having  a  bridge  or 
bar  dividing  the  spout  from  the  body;  the  Craven  and 
Chapman  is  one;  the  other,  Goodwin  and  How's,  is 
illustrated  in  Figs.  26  and  27.  From  these  it  is  seen 
that  the  body  of  the  ladle  is  pear-shaped,  the  shell  being 
extended  on  one  side  to  form  an  external  spout,  which  is 
separated  from  the  body  by  a  skimmer  or  dividing  plate, 
projecting  above  the  top  of  the  shell,  and  descending  to 
the  required  distance  from  the  bottom.  It  is  held  in 
position  by  eyes,  pins,  and  cotters  at  the  top,  and 
by  finger  plates  at  the  bottom.  The  skimmer  plate  is 
readily  removable  for  repairs.  The  principle  of  taking 
the  metal  from  the  bottom  is  an  excellent  one,  and  has 
long  been  adopted  in  the  steel-casting  ladles,  fitted  with 
a  goose  neck  and  plug. 


CHAPTER  V 

THE  SHOPS,  AND  THEIR  EQUIPMENT 

Situation. — When  designing  an  iron  foundry,  everything 
must  depend  upon  situation  and  upon  the  space  avail- 
able; but  there  are  certain  main  considerations  which 
may  be  briefly  stated.  In  the  first  place,  the  soil  ought 
to  be  dry.  One  of  the  greatest  difficulties  in  some  low- 
lying  districts  is  to  get  a  sufficiently  dry  site.  This, 
which  is  a  matter  of  slight  consequence  in  the  building  of 
a  machine  shop  or  boiler  shop,  is  of  serious  import  when 
a  foundry  is  concerned.  In  spongy  ground,  and  ground 
liable  to  floods,  moulds  sunk  in  the  floor  are  always 
liable  to  damage.  In  such  cases  new  ground  should  be 
made  up  of  a  height  sufficient  to  be  above  the  reach  of 
water,  and  especial  care  be  taken  in  so  lining  the  casting 
pits  as  to  render  them  impervious  to  moisture. 

The  building  also  ought  to  be  lofty  and  well  ventilated, 
to  carry  off  the  sulphurous  fumes  and  smoke  present  in 
all  foundries.  There  should  be  plenty  of  light.  Ven- 
tilation and  light  are  as  essential  in  a  foundry  as  in  a 
machine  shop.  Both  should  be  mainly  provided  in  the 
roof.  A  foundry  cannot  be  too  well  lighted.  So  much  of 
the  work  is,  in  itself,  involved  in  shadow,  as  in  deep  lifts, 
setting  of  cores,  etc.,  that  even  in  the  best-lighted  shop 
the  use  of  lamps  in  the  daytime  is  frequently  necessary. 
If  the  roof  is  well  lighted,  little  side  light  is  required. 
Still,  the  more  the  better,  and,  whenever  practicable,  side 


72  PRACTICAL  IRON  FOUNDING 

windows  should  be  included.  Further,  the  building  should 
be  of  the  same  section  throughout,  in  order  that  a  tra- 
velling crane  may  run  from  end  to  end  without  hind- 
rance. Again,  if  a  large  area  is  required,  it  is  better  to 
obtain  that  by  giving  increase  in  width  rather  than  ex- 
cessive increase  in  length,  and  this  not  by  unduly  widen- 
ing a  single  span,  but  by  doubling  or  trebling  the  spans, 
either  making  two  of  equal  breadth,  or  flanking  a  main 
span  with  one  or  with  two  narrower  side  ones,  according 
to  circumstances.  This  arrangement  is  economical  in 
respect  of  the  carrying  of  metal  and  materials,  flasks, 
and  tackle ;  and  it  permits  also  of  better  overlooking  and 
supervision.  In  any  span  there  should  always  be  clear 
floor  room  throughout,  and  this  is  of  prime  importance. 
To  have  cranes  stuck  about  in  the  middle  of  a  shop  is  a 
bad  arrangement,  because  they  occupy  valuable  room, 
and  make  the  transit  of  metal  awkward. 

But  these  general  conditions  often  have  to  be  modified 
by  circumstances,  because  the  planning  of  any  workshop 
may  be  hampered  by  the  ground  plan  of  the  premises. 
The  proximity  of  certain  departments  is  desirable,  and 
parallel  bays  are  not  always  practicable. 

Enlargement. — The  possibility  of  future  enlargement 
must  be  considered  in  laying  out  a  new  foundry.  And 
extension  can  only  be  effected  on  the  ground.  No  shops 
can  be  built  over,  because  the  heat  and  sulphurous 
fumes  forbid  it.  Future  extension  must  be  provided  for, 
longitudinally,  or  laterally,  by  increasing  the  length  of  a 
bay,  or  by  adding  a  new  bay  or  bays  at  the  sides  of  the 
primitive  building.  A  beginning  can  be  made  with  a 
square  building,  equipped  with  a  central  crane,  and  one 
or  two  wall  cranes.  That  is  not  a  very  good  plan,  but 
many  small  shops  are  constructed  thus.  In  a  future 


THE  SHOPS,  AND  THEIR  EQUIPMENT        73 

extension  the  shop  would  be  made  oblong,  and  the  crane 
would  remain  to  serve  the  heavy  loam  work,  while  the 
added  length  might  be  served  with  a  traveller  and  light 
wall  cranes.  When  starting  a  block  of  buildings,  the 
proximity  of  stores,  etc.,  must  be  borne  in  mind  to  save 
unnecessary  handling  of  materials. 

Cupolas. — Two  cupolas  are  necessary  in  any  foundry. 
The  smaller  will  be  of  about  2  ft.  6  in.  diameter,  the 
larger  will  range  up  to  4,  5,  6,  or  7  ft.,  according  to  the 
weight  of  work  done.  In  a  large  foundry  two  cupolas  or 
more  of  the  largest  capacity  may  be  required  for  the 
day's  casts.  Besides  these,  it  is  often  convenient  to  have 
a  small  one  of  from  16  to  18,  or  24  in.  diameter,  having 
a  capacity  of  from  10  to  30  cwt.,  for  the  purpose  of  mak- 
ing tests  of  mixtures,  casting  test  bars,  making  a  special 
light  cast,  etc. 

Generally  it  is  convenient  to  locate  the  cupolas  to- 
gether for  convenience  of  charging  and  blowing.  Inside 
the  foundry  it  would  often  be  more  convenient  for  the 
tapping  of  metal  to  locate  cupolas  apart  from  one  another. 
In  the  case  of  special  departments  of  work,  such  arrange- 
ments must  sometimes  be  made.  The  general  rule,  how- 
ever, is  to  set  cupolas  together,  as  nearly  centrally  as 
possible,  in  order  to  lessen  the  distance  of  carriage  of  the 
metal,  and  the  loss  of  blast  pressure.  In  many  foundries 
the  practice  is  to  locate  the  cupolas  without  the  building, 
passing  the  tapping  shoot  through  the  wall  into  the  in- 
terior. In  others  the  lower  portions  are  within  the  build- 
ing, and  the  upper  parts  pass  out  through  the  roof.  The 
latter  has  the  advantage  over  the  former,  that  the  furnace- 
men  are  protected  from  weather,  and  that  the  foreman 
can  observe  the  melting  without  going  outside.  But  if 
the  cupolas  are  placed  without,  a  door  at  the  side  permits 


74  PRACTICAL  IRON  FOUNDING 

ready  egress,  Hydraulic  hoists,  or  geared  pulley-driven 
hoists,  will  be  located  at  the  cupola  stagings  for  lifting 
iron  and  coke  from  below. 

Large  ladles  of  metal  are  carried  away  with  the  tra- 
veller, or  with  a  walking  crane,  or  swung  round  in  a  jib 
crane  to  moulds  within  its  radius.  Light  casting  is  some- 
times done  from  a  tipping  ladle  on  a  bogle  running  on 
rails  down  the  shop.  The  moulds  are  either  poured 
directly  from  the  ladle,  or  it  is  used  to  supply  the  smaller 
hand  ladles  which  fill  the  moulds  in  its  passage  down  the 
shop.  Shank  ladles,  containing  from  56  Ib.  to  4  cwt.  are 
generally  carried  by  hand. 

Core  Ovens. — The  dimensions  of  core  ovens  and  drying 
stoves  depend  upon  the  nature  of  the  work  done  in  a 
given  foundry.  The  largest  stoves  run  to  20  ft.  or  24  ft. 
long,  by  from  10  ft.  to  12  ft.  wide.  Height  also  will  de- 
pend on  the  class  of  work,  ranging  from  6  ft.  to  10  ft. 
Carriages  will  occupy  from  1  ft.  to  2  ft.  of  this  height. 
In  cases  where  work  exceeds  6  ft.  or  8  ft.  in  height,  it  is 
usual  to  effect  a  division  in  the  mould,  parting  it  into 
two,  which  are  placed  separately  on  the  carriage.  The 
largest  stoves  should  be  adjacent  to  the  area  where  loam 
work  is  done.  The  smallest  stoves  are  better  located  else- 
where, adjacent  to  the  small  core-making  departments,  to 
be  used  for  the  drying  of  cores,  or  of  small  moulds.  The 
stoves,  except  those  for  very  small  cores,  are  always 
built  outside  the  foundry,  the  doors  being  flush  with  the 
interior  of  the  foundry  walls.  Stoves  are  fired  with  coke 
from  the  outside — that  is,  from  the  end  farthest  from  the 
doors.  In  some  cases,  however,  the  grate  is  built  inside 
in  the  centre  of  the  floor.  The  neatest  way  of  firing  is  by 
producer  gas,  or  the  waste  gas  from  furnaces.  The  car- 
riages containing  the  cores  are  made  in  cast  iron,  framed 


THE  SHOPS,  AND  THEIR  EQUIPMENT        75 

together,  and  covered  with  loose  plates.  They  are  run  in 
on  rails  which  lead  from  the  shop  into  the  stove.  Pro- 
vision is  made  in  some  foundries  for  drying  large  moulds 
in  the  foundry  pits.  The  latter  are  of  large  area,  and  are 
heated  by  gas,  being  covered  over  with  iron  plates  during 
the  drying  process. 

Tracks. — Narrow  bogie  tracks  might  advantageously 
be  used  to  a  greater  extent  than  they  are  in  English 
foundries.  The  objection  to  their  use  is  that  they  occupy 
some  floor  space  that  might  be  required,  and  that  the 
ladles  are  apt  to  spill  some  of  their  contents  if  the  track 
becomes  temporarily  obstructed.  In  reference  to  the 
first,  a  fairly  clear  way  down  the  centre  of  the  shop  must 
of  necessity  be  kept  for  the  transit  of  materials,  and  of 
metal  if  carried  in  hand  ladles.  In  reference  to  the 
second,  mishaps  need  not  occur  if  a  labourer  is  made  re- 
sponsible for  keeping  the  ways  clear.  Also,  similar  mis- 
haps occur  with  hand-carried  ladles.  Further,  too,  other 
materials  beside  metal  are  carried  on  the  tracks,  and 
tackle  also.  The  advantages  are:  Facility  in  transit, 
avoiding  the  changing  of  heavy  ladles  from  one  crane  to 
another  and  saving  in  labour,  one  man  being  able  to 
push  along  a  load  which  would  require  three  or  four  men 
to  carry  in  shank  ladles  and  by  hand.  In  the  light 
foundry  more  especially,  the  tracks  are  of  value,  since  a 
ladle  carrying  5  cwt.,  8  cwt.,  or  10  cwt.  of  metal  can  be  run 
over  from  the  cupola  and  made  to  feed  a  dozen  or  twenty 
small  moulds  ranged  along  its  track.  For  small  moulds 
not  in  the  line  of  track,  the  light  561b.  hand  ladles  can 
he  dipped  into  the  larger  ladle  close  by,  instead  of  run- 
ning across  to  the  cupola  with  them.  Probably  most  of 
our  readers  know  that  one  of  the  largest  foundries  in 
England — that  at  Ore  we — has  tiny  locomotives  running 


76  PRACTICAL  IRON  FOUNDING 

on  its  tracks.  Not  only  for  pouring,  but  also  for  running 
along  flasks,  sand  boxes,  and  other  material,  is  the  track 
serviceable,  saving  hand-carrying  for  light  loads  and  fre- 
quent waiting  for  the  traveller  to  be  at  liberty  for  heavy 
ones. 

With  rare  exceptions  the  tracks  are  always  narrow, 
seldom  exceeding  about  18  inches  gauge.  The  rails  are 
either  cast  on  plates,  or  they  are  fitted  on  cross-sleepers. 
Casting-on  is  a  convenient  device  for  several  reasons.  The 
rails  may  stand  above  the  plates,  or  preferably  be  flush, 
flanked  by  recesses  for  the  wheel  flanges.  Such  tracks 
are  arranged  to  connect  with  the  yard  tracks  and  thence 
with  the  other  shops  of  the  works. 

The  narrow-gauge  tracks  may  run  uniformly  through- 
out the  works,  or  not  go  beyond  the  shop  doors,  as  when 
wide-gauge  standard  tracks  serve  the  yard.  These  then 
come  up  to  the  foundry  doors  so  that  articles  can  be 
loaded  and  unloaded  from  standard  to  narrow  and  vice 
versa.  Suitable  trolleys  are  built  for  foundry  service,  being 
plain,  or  with  sides  to  suit  different  classes  of  castings. 

Casting  pits. — These  are  either  oblong,  circular,  or 
polygonal  in  form,  and  their  purpose  is  twofold.  The 
oblong  pits  are  comparatively  shallow,  but  of  large  area, 
and  are  used  for  moulding  work  which  has  to  be  dried, 
but  which  is  so  massive  that  it  could  not  be  dried  in  the 
ordinary  core  stove,  or,  if  dried,  could  not  be  moved  from 
the  floor  to  the  pit.  Hence  it  is  rammed,  dried,  and  cast 
in  situ.  The  circular  and  polygonal  pits  are  usually  very 
much  deeper  than  the  oblong  pits,  and  the  work  may  or 
may  not  be  moulded  and  dried  in  them,  but  is  as  a  rule 
moulded  on  the  floor,  dried  in  the  drying  stove,  and  only 
lowered  into  the  pit  finally  for  casting.  The  oblong  pits 
being  shallow,  are  generally  lined  only  with  brickwork, 


THE  SHOPS,  AND  THEIR  EQUIPMENT         77 

except  in  damp  and  low-lying  situations  where  water 
could  gain  access,  when  they  are  of  iron.  They  are 
covered  over  with  movable  plates  of  cast  iron  to  confine 
the  heat  while  drying,  and  are  dried  with  gas.  The  deep 
pits,  on  the  contrary,  have  no  covering,  being  simply 
receptacles  for  finished  moulds;  but,  being  deep,  they 
are  often  liable  to  the  entrance  of  water,  and  are 
therefore  lined  throughout  with  iron  plates,  consisting 
either  of  boiler  plates  riveted  together  in  the  form  of  a 


FIG.  28.— FOUNDRY  PIT. 

cylinder,  or  of  cast-iron  plates  bolted  together  with  flanges 
like  tank  plates  (Fig.  28).  The  bottom  is  similarly  formed 
of  iron  plates. 

When  bricking-up  work  in  the  pit  it  is  often  necessary 
to  erect  staging  at  intervals  for  the  men  to  stand  upon 
while  working;  ladders,  also,  are  sometimes  placed  in  the 
pit,  and  planks  laid  across  the  rungs,  but  it  is  better  to 
make  provision  when  building  the  pit  for  such  staging. 
When  boiler  plate  is  used,  rings  of  angle  iron  can  be 
riveted  around  at  various  heights  for  this  special  pur- 


78  PRACTICAL  IRON  FOUNDING 

pose;  ribs  may  be  cast  on  cast-iron  plates  when  such  are 
employed,  or  the  pit  itself  may  be  constructed  with  rings 
or  plates,  the  diameter  of  which  increases  as  the  series 
ascends,  so  as  to  form  ledges  at  intervals  all  the  way  up. 

When  it  is  required  to  diminish  the  size  of  a  large  pit 
for  a  temporary  purpose  in  order  to  put  a  small  job  in, 
loose  rings  are  lowered  down  and  the  work  rammed  up 
inside  them  as  at  A  (Fig.  28).  Large  casting  pits  will 
range  from  30  ft.  to  70  ft.  in  length,  by  from  18  ft.  to  22  ft. 
in  width;  small  ones  from  8  ft.  to  12  ft.  or  14  ft.  in 
diameter. 

Offices,  etc. — The  foreman's  office  should  overlook  the 
entire  shop,  and  be  roomy  enough  to  permit  of  the  mak- 
ing of  tests,  and  for  the  clerical  work  of  the  foundry. 

The  pattern  bench  never  need  be  large.  Patterns  ought 
not  to  lie  about  long  in  the  foundry.  The  foundry  bench 
is  not  a  store,  but  simply  a  receptacle  for  jobs  wanted, 
and  as  soon  as  they  are  done  with  they  should  be  cleared 
away  from  the  shelving  and  a  fresh  supply  of  patterns 
sent  in. 

Narrow  shelving — one  or  two  rows — is  arranged  round 
the  walls  for  the  reception  of  small  patterns  after  mould- 
ing, and  a  few  moulders'  small  requisites — lamps,  nails, 
etc.  As  soon  as  the  castings  are  turned  out  and  passed, 
the  patterns  must  be  removed,  otherwise  loose  pieces  will 
be  lost  and  parts  damaged. 

Stores  for  the  foundry,  and  the  various  machinery  for 
the  same,  should  be  located  close  to  the  building,  in  such 
a  manner  that  time  will  not  be  wasted  in  obtaining  any- 
thing required  Coke,  sand,  iron  will  be  kept  in  sheds, 
and  the  machines  for  grinding,  mixing,  and  breaking 
will  be  adjacent,  and  rails,  trucks,  and  hoists  will  convey 
the  materials  whenever  required.  The  sand  and  other 


THE  SHOPS,  AND  THEIR  EQUIPMENT        79 

sheds  may  open  into  the  foundry,  or  may  be  located  out- 
side. There  is  so  much  dust,  dirt  and  litter  attending 
these,  that  it  seems  better  to  have  them  to  open  outside 
the  foundry  than  into  it,  adjacent  to  the  work  of 
moulding. 

The  fettling  shop  must  always  be  parted  from  the 
foundry  itself.  The  reason  is  that  the  chips,  the  fins,  etc., 
that  are  chipped  off  the  castings  must  not  be  permitted 
to  mix  with  the  foundry  sand.  In  the  fettling  shop  there 
will  be  a  bench  with  vices,  small  emery  wheels  for  grind- 
ing off  fins,  scabs,  etc.,  and  a  tumbler  or  rattle  barrel  for 
cleaning  off  sand  and  smoothing  surfaces. 

The  location  of  the  pig  and  scrap  iron  will  depend  on 
local  conditions.  It  is  not  necessary  that  the  iron  shall 
be  close  to  the  cupolas.  It  may  be  elsewhere,  provided  a 
track  is  brought  from  the  iron  stores  to  the  cupola. 

Departments. — If  there  are  specialities  in  firms,  as 
there  are  in  most  cases  nowadays,  each  should  be  con- 
fined to  a  separate  department.  This  is  simply  an  exten- 
sion of  the  principle  of  keeping  in  a  general  shop  certain 
men  on  certain  classes  of  jobs.  Thus,  wheel  moulding, 
cylinder  moulding,  light  green-sand,  heavy  green-sand, 
etc.,  will  be  done  by  men  who  will  be  kept  as  far  as  prac- 
ticable each  on  his  class  of  work.  To  keep  separate 
classes  of  work  in  separate  departments  follows  naturally 
as  the  volume  of  trade  increases.  Sometimes  these  de- 
partments will  be  located  in  separate  buildings,  or  in 
different  portions  of  a  single  building.  It  is  always  de- 
sirable to  make  a  distinction  between  light  and  heavy 
work,  because  that  permits  of  a  suitable  arrangement 
of  hoisting  tackle,  flasks,  proportion  of  unskilled  labour 
required,  and  so  on.  Loam  work  must  always  be  kept 
distinct  from  everything  else,  because  of  the  special 


80  PRACTICAL  IRON  FOUNDING 

tackle  required,  the  ground  area  occupied,  the  proximity 
of  drying  stoves  and  casting  pits,  and  heavy  hoisting 
tackle,  and  because  of  the  dust  created  in  filing  and 
finishing  moulds.  Plate  moulding,  with  or  without  the 
aid  of  machines,  requires  its  own  special  area  and  tackle. 
So  does  railway-chair  work,  ploughshare  work,  malle- 
able cast  iron  work,  etc.  Engine  cylinders,  liners,  and 
slide  valves,  also,  when  made  in  large  numbers,  should 
have  a  separate  shop,  and  a  cupola  for  the  melting  of 
special  metal.  Brass  work  is  always  relegated  to  a  dis- 
tinct shop. 

Everything  which  can  be  kept  under  cover  should  be 
so  kept.  A  considerable  weight  of  metal  is  lost  in 
rust  every  year  when  tackle  is  left  in  the  open.  Standard 
grids,  core  bars,  and  the  smaller  flasks  can  all  be  kept 
in  sheds  without  encroaching  on  the  foundry  area. 

Foundry  doors  must  be  made  amply  large  enough  to 
pass  the  largest  patterns  or  castings  ever  likely  to  be 
constructed.  The  main  doors  should  not,  as  a  rule,  be 
less  than  12  to  14  ft.  wide,  and  from  10  to  12  ft.  high. 
They  are  made  of  sheet  iron  to  slide  sideways,  or  ver- 
tically; in  the  latter  case  being  counterweighted.  Hinged 
doors  should  never  be  used.  Smaller  doors  will  be  placed 
at  various  parts  to  suit  various  requirements. 

The  average  foundry  is  almost  invariably  the  most 
badly- equipped  of  any  engineer's  department  in  regard 
to  labour-saving  appliances.  There  are  foundries  now, 
considered  good,  in  which  there  is  no  machinery  and  no 
labour-saving  appliances  worth  mentioning — in  which 
work  is  carried  on  by  precisely  the  same  methods  which 
were  in  operation  a  quarter  of  a  century  ago,  and  where 
everything  is  still  done  by  dint  of  pure  physical  effort; 
moulds  made,  metal  carried,  castings  cleaned,  etc.,  with- 


PLATE  III 


See  p.  0f>  [Facing  p. 

FIG.  20. — LADLES,  BY  THWAITES  BROS.,  LTD. 


THE  SHOPS,  AND  THEIE  EQUIPMENT        81 

out  the  most  obvious  economies  which  have  long  been 
practised  in  the  leading  firms.  If  a  fractional  part  of 
the  money  which  is  lavished  in  the  other  departments 
to  save  unskilled  labour  were  spent  in  the  foundry  to 
lessen  the  cost  of  skilled  labour  there,  the  results  would 
in  time  prove  eminently  satisfactory.  The  reason  why 
this  condition  of  things  exists  is  that  the  class  of  work 
done  in  pattern  shop  and  foundry  is  of  a  different  char- 
acter from  that  carried  on  in  the  boiler  and  machine 
shop,  in  this  respect — that  the  work  is  not  usually  so  re- 
petitive there  as  in  these. 

There  is  some  machinery  which  is  indispensable  in 
any  foundry.  There  is  much,  also,  of  a  more  or  less 
special  character,  the  cost  of  which  is  either  too  heavy 
for  small  foundries,  or  else  it  is  machinery  which  is 
adapted  only  for  certain  classes  of  work. 

Indispensable  machines  are  the  coal  mill  and  loam 
mill.  Those  which  are  seldom  used  in  small  foundries, 
but  which  are  found  in  most  large  ones,  are  sand-sifters, 
emery  wheels,  rattle  barrels,  testing  machines,  and  ma- 
chines for  breaking  pig  iron  and  coke.  Machines  of  a 
special  character  used  in  special  departments  of  large 
foundries  doing  general  work,  and  in  any  shops  doing 
special  work,  are  the  plate-moulding  and  the  wheel- 
moulding  machines.  Articles  which  come  under  the 
head  of  appliances,  and  which  are  essential  everywhere, 
are  wheel-barrows,  ladles,  shovels,  riddles,  sieves,  scratch 
brushes,  core  trestles,  iron  core  boxes,  flasks,  etc. 

Cranes. — These  are  of  three  kinds — post  cranes,  which 
slew  completely  round;  wall  cranes,  which  slew  within 
a  more  limited  range,  generally  180  degrees;  and  over- 
head travelling  cranes,  the  range  of  travel  of  which  covers 
the  whole  of  the  floor  area  of  the  shop.  The  post  cranes 


82  PRACTICAL  IRON  FOUNDING 

are  very  useful  when  the  shop  is  of  moderate  size  and  of 
quadrangular  form.  The  framework,  triangular  in  out- 
line, may  be  constructed  either  of  steel  or  of  wood.  The 
post  is  pivoted  in  a  toe  step  in  the  ground,  and  in  a 
socket  attached  to  cross  timbers  in  the  roof  trusses.  Pro- 
vision is  made  for  lifting  by  single  and  double  gear,  and  for 
racking  inwards  and  outwards;  the  latter  being  essential 
for  the  precise  adjustment  of  the  ladles  in  relation  to 
the  moulds,  which  are  arranged  on  the  floor.  The  power 
of  such  cranes  may  range  from  three  to  fifteen  tons. 

The  wall  cranes  are  necessarily  of  light  construction, 
ranging  between  powers  of  one  and  two  tons  only. 
The  framework  consists  of  horizontal  jib,  and  ties  only, 
made  in  steel.  The  hoisting  gears  are  attached  to  a 
bracket  which  is  bolted  to  the  wall,  independently  of 
the  main  framework.  A  racking  carriage  travels  on  the 
horizontal  jib,  and  is  worked  by  means  of  an  endless  rope 
depending  from  a  spider  wheel  above.  These  are  used 
for  turning  over  and  lifting  the  light  moulds,  and 
smaller  ladles,  and  if  ranged  in  series,  each  within  range 
of  the  radius  of  its  fellow,  ladles  can  be  passed  down 
the  shop  rapidly,  being  transferred  from  crane  to  crane 
with  changing  hooks. 

But  the  overhead  traveller  has  the  best  arrangement 
for  all  except  the  very  small  shops.  The  traveller  moves 
along  the  gantry  beams  which  are  supported  on  the 
stone  abutments  of  the  walls,  and  the  crab  has  a  trans- 
verse motion  across  the  traveller  beams.  The  whole 
area  of  the  floor  can  thus  be  covered  at  will.  Travellers 
when  of  small  size  are  worked  by  hand  from  below 
with  endless  ropes,  many  of  those  of  larger  size  by  a  man 
stationed  on  the  crab  above.  Travellers  of  all  sizes  are 
now  actuated  electrically. 


THE  SHOPS,  AND  THEIR  EQUIPMENT        83 

These  will  be  differently  arranged  according  to  cir- 
cumstances. There  should  be  at  least  one  overhead 
traveller  in  each  bay,  operated  by  hand  or  by  electricity. 
It  is  well  to  have  two  travellers — one  light  and  one 
heavy — in  long  shops  where  a  lot  of  handling  of  flasks 
has  to  be  done.  In  addition  there  must  be  several  hand, 
electric,  or  hydraulic  cranes.  Columns  can  be  utilized 
for  the  attachment  of  cranes  which  swing  in  a  complete 
circle  to  serve  adjacent  bays.  It  is  necessary  to  have 
jib  cranes,  as  well  as  a  traveller,  in  a  foundry  bay,  be- 
cause a  single  traveller  cannot  serve  all  the  requirements 
of  a  foundry.  They  should  not  be  in  the  middle  of  the 
shop,  because  they  would  be  in  the  way.  If  a  crane  is 
placed  in  the  centre  of  a  bay  it  must  be  located  at  one 
end,  in  order  not  to  interfere  with  the  work  of  the 
traveller,  or  with  the  clear  floor  area  necessary.  At  one 
end  it  may  serve  for  the  heavy  loam  work,  or  heavy 
green-sand  work.  Any  jib  crane  which  is  adjacent  to 
another  crane  should  cover  its  radius,  for  the  conveni- 
ence of  changing  flasks  or  ladles  from  one  to  another. 
All  jib  cranes  must  have  racking  movement  to  cover  any 
work  lying  between  the  post  and  the  maximum  radius, 
and  therefore  they  must  have  horizontal  jibs.  Walking 
cranes  are  sometimes  used  in  foundries,  as  in  machine 
shops  and  turneries.  They  cover  the  whole  area  without 
remaining  a  permanent  block.  But  they  are  not  so  well 
adapted  for  heavy  work  as  the  travellers. 

Converted  and  single-motor  travellers  are  undesirable. 
Each  motion, — hoisting,  longitudinal,  and  cross  traverse 
should  have  its  own  motor,  and  a  heavy  traveller  should 
have  in  addition  an  auxiliary  hoist  for  light  loads. 

Poiver. — In  making  selection  of  power  for  a  foundry 
at  the  present  time,  broader  views  have  to  be  taken  than 


84  PRACTICAL  IRON  FOUNDING 

formerly.  Not  only  have  new  applications  of  power 
agencies  come  into  the  field,  but  the  foundry  itself  has 
been  radically  reorganized  and  remodelled.  Many  recent 
foundries  are  machine-moulding  shops ;  others  have  gone 
far  in  that  direction.  Human  muscle — a  big  asset  in  the 
older  shops — is  of  less  account  now  than  it  was  at  one 
time.  Mechanical  aids  to  lift  and  carry  are  ubiquitous. 
As  foundries  have  been  re-designed,  so  also  have  power 
agencies  become  readapted. 

One  fact  should  seem  so  obvious  as  hardly  to  need 
stating,  namely,  that  no  single  answer  can  be  given  to 
the  question  that  would  be  of  universal  application. 
There  is,  for  example,  very  little  in  common  between  a 
foundry  doing  all  light  work  and  another  handling  only 
heavy  work.  A  foundry  which  deals  with  both  classes 
stands  in  a  different  category  from  one  manufacturing 
specialities,  and  so  on.  Each  shop  must  be  considered 
as  an  entity  apart  from  any  other.  The  following  re- 
marks are  intended  to  embrace  the  principal  conditions 
which  exist  in  foundries. 

The  natural  course  to  adopt  in  approaching  the  power 
question  is  to  take  first  a  brief  survey  of  the  services  for 
which  power  is  demanded  or  is  desirable.  These  are 
hoisting  and  carrying  power  for  the  cupola,  machinery 
for  the  preparation  of  materials,  machinery  for  making 
moulds,  and  that  for  cleaning  castings. 

Hoisting  and  carrying  machinery. — These  are  included 
under  one  heading  because  they  are  intimately  related, 
though .  carrying  on  tracks  is  independent  of  hoisting. 
But  all  cranes  carry  as  well  as  lift,  and  one  of  the  prin- 
cipal differences  in  them  lies  in  their  range  of  action, 
which  is  least  in  a  swinging  crane,  and  greatest  in  over- 
head travelling  cranes,  and  hoists  on  overhead  tracks. 


THE  SHOPS,  AND  THEIR  EQUIPMENT        85 

The  power  agencies  include  hand,  steam,  electricity, 
compressed  air,  and  pressure  water. 

Hand  power. — Hand  power  cannot  be  left  out  of  ac- 
count, because  small  foundries  in  country  places  depend 
mainly  upon  it.  Such  foundries  are  not  able  to  afford 
an  expensive  power  plant  of  any  kind.  The  demands  for 
crane  service  are  too  limited,  too  intermittent,  to  justify 
the  capital  outlay  involved.  For  these  the  hand-operated 
overhead  travelling  crane  offers  a  cheap  source  of  power. 
It  is  made  to  be  operated  by  a  labourer  on  the  crab,  or 
from  the  floor  by  a  dependent  chain.  A  swinging  jib 
crane,  or  two,  judiciously  located  against  walls,  to  cover 
certain  areas  where  such  help  is  most  needed,  may  well 
supplement  the  overhead  traveller.  Such  cranes  must 
have  horizontal  jibs  along  which  the  jenny  can  be 
racked.  Neither  cranes  with  fixed  jibs,  nor  derrick  cranes 
with  luffing  jibs,  are  suitable  for  foundry  service.  In 
shops  equipped  with  hand  cranes  the  power  which  can 
be  most  economically  installed  is  a  steam-engine  for 
driving  the  blower,  the  sand  and  coke  mills,  and  tum- 
blers. This  is  the  simplest  and  cheapest,  the  driving 
then  being  done  by  means  of  belts.  This  machinery, 
small  in  amount,  but  indispensable,  can  be  located 
adjacent  to  the  blower  and  cupola,  preferably  in  a  shed 
outside  the  foundry  wall. 

Steam  power. — Steam  power  may  be  ruled  out  entirely 
now  in  all  ordinary  foundries  of  medium  and  large  di- 
mensions for  new  installations  of  hoisting  machines. 
Electricity  has  almost  wholly  superseded  it,  and  where 
this  is  installed  it  serves  also  for  the  driving  of  the 
blower  and  the  grinding  mills.  Overhead  steam  tra- 
vellers and  rope -driven  ones  were  always  somewhat 
of  a  nuisance,  which  accounts  for  the  rapidity  with 


86  PRACTICAL  IRON  FOUNDING 

which  they  disappeared  as  methods  of  electric  driving 
improved. 

Electric  power. —  Electricity  is  the  agent  which  in 
foundries,  as  in  other  shops,  is  the  most  flexible  and 
mobile  form  of  power.  The  work  of  the  foundry  is  more 
intermittent  than  that  of  the  machine  shop,  and  elec- 
tricity is  eminently  adaptable  to  such  conditions.  At 
casting  time,  and  when  castings  are  being  removed  from 
their  moulds,  the  cranes  are  fully  occupied.  During  the 
middle  of  the  day  their  service  is  intermittent.  When 
electric  cranes  are  not  running  they  are  using  no  power, 
and  when  in  operation  they  absorb  only  the  amount 
which  corresponds  with  the  demands  made  upon  them. 
Also,  nearly  all  cranes  now  built  have  separate  motors 
for  each  motion,  and  for  heavy  and  light  loads,  rated 
suitably  for  the  different  speeds  and  loads,  thus  not  only 
economizing  power,  but  getting  the  most  suitable  speeds 
for  every  separate  motion. 

The  distribution  of  electric  power  from  the  power 
house  entails  the  employment  of  a  considerable  number 
of  motors  distributed  where  required.  But  against  their 
cost  is  to  be  set  the  fact  that  they  are  eminently  adapted 
to  foundry  service  where  the  cranes  and  machinery  are 
scattered  and  used  very  intermittently,  and  they  compare 
in  this  respect  most  favourably  with  any  other  method  of 
power  distribution.  In  a  large  foundry  the  average  load 
on  the  motor  is  low,  because  the  intermittent  periods 
when  no  power  is  being  used  are  frequent  and  long  in 
the  case  of  almost  all  machines. 

In  a  large  foundry  the  facilities  for  transmission  which 
the  electric  cables  afford  contrast  most  favourably  with 
those  of  steam  pipes,  square  shafts,  or  cotton  ropes. 
One  power  house  will  supply  all  the  current  required 


THE  SHOPS,  AND  THEIR  EQUIPMENT        87 

for  cranes,  blowers,  and  machinery  used  in  the  foundry. 
Cables  supply  the  cranes  with  current,  which  is  switched 
on  to  motors  on  the  cranes  only  when  required  for 
service. 

Blowers  and  various  machines  are  belted  preferably 
from  short  lengths  of  motor-driven  shafting  suitably  dis- 
posed. Blowers  are  designed  to  suit  every  kind  of  drive. 
A  motor  is  directly  coupled  to  the  blower  shaft,  or  it  is 
driven  through  one  set  of  reduction  gear,  or  a  belt  drive 
is  taken  from  a  countershaft  above,  or  from  a  counter- 
shaft on  the  same  bedplate  as  the  blower,  with  provision 
for  belt  tightening.  Or  a  steam-engine  often  drives  the 
blower  direct,  being  mounted  on  the  same  bedplate. 

These  variations  are  adaptable  to  different  local  con- 
ditions, and  the  reason  why  the  blower  is  thus  favoured 
lies  in  the  desirability  of  locating  it  in  a  room  by  itself, 
away  from  other  machines,  in  order  to  prevent  access  of 
dust  to  the  interior.  The  sand  and  coal-grinding  mills 
are  better  belted  from  a  motor-driven  countershaft.  The 
machines  in  the  fettling  shop  are  similarly  operated. 

Compressed  air. — This  is  a  source  of  power  which  is 
almost  indispensable  in  any  foundry  of  ordinary  dimen- 
sions, apart  from  its  utilities  in  operating  light  hoisting 
machinery  running  on  overhead  tracks,  and  in  some 
types  of  moulding  machines.  The  utilities  of  pneumatic 
rammers,  and  of  pipes  for  blowing  loose  sand  away  from 
pattern  faces  and  out  of  moulds,  are  of  much  value,  as 
also  is  the  sand  blast  for  fettling  castings.  These  alone 
are  sufficient  to  justify  the  pneumatic  installation. 
Whether  to  extend  the  system  to  the  operation  of  hoists 
and  of  moulding  machines  must  be  answered  differently 
in  different  foundries. 

The  light  pneumatic  hoists  on  overhead  tracks,  covering 


88  PRACTICAL  IRON  FOUNDING 

the  entire  floor  area,  are  a  great  help  in  many  foundries. 
But  since  electric  power  has  been  installed  so  generally, 
electric  hoists  have  often  been  preferred.  The  electric 
cable  is  to  be  preferred  to  air- supply  pipes  with  their 
risks  of  leakages.  The  elasticity  of  the  air  lift,  though 
not  very  marked  in  the  best  modern  hoists,  is  still  ob- 
jectionable when  withdrawing  patterns,  and  when  turn- 
ing over  boxes  of  moulds. 

On  the  other  hand,  the  cost  of  pneumatic  hoists  is 
less  than  that  of  electric  ones,  which  have  to  include 
one  or  two  motors,  besides  gears.  Electric  hoists  are, 
however,  better  suited  to  the  heavier  loads  than  pneu- 
matic types.  Compressed  air  is  used  in  many  power- 
rammed  machines,  and  its  use  is  increasing.  But  many 
firms  prefer,  or  are  committed  to,  hand  machines.  Then 
the  air  hose  should  be  an  adjunct  for  blowing  surplus 
sand  out  of  the  moulds. 

Hydraulic  power. — Pressure  water  is  used  very  largely 
in  German  foundries.  The  reason  of  this,  apparently, 
is  that  in  the  German  shops  heavy  machine  moulding 
has  developed  more  extensively  than  in  any  other  coun- 
try, and  for  this,  hydraulic  pressure  has  no  rival.  But 
apart  from  this  service,  pressure  water  is  now  rarely 
installed  in  foundries;  that  is,  it  would  seldom  be  used 
for  cranes,  unless  already  in  use  or  contemplated  for 
heavy  moulding  machines. 

Formerly,  in  a  fair  number  of  foundries,  hydraulic  jib 
cranes  were  employed,  and  they  have  the  advantage  of 
being  easily  and  minutely  controlled.  But  there  are 
several  disadvantages  incidental  to  the  pipe  connections 
and  valves,  and  the  liquid  used,  and  the  system  is  not 
adaptable  to  the  other  services  of  the  foundry — the  over- 
head travellers  and  the  blowers  and  machines.  The 


THE  SHOPS,  AND  THEIR  EQUIPMENT        89 

combination  of  steam  with  water,  the  steam-hydraulic 
system,  has  been  employed  rather  extensively;  but  the 
disadvantages  of  the  transmission  apply  to  this  as  to 
the  hydraulic,  comparing  unfavourably  with  the  electric 
conductor. 

Miscellaneous  machines. — Cupola  hoists  are  operated 
by  whatever  source  of  power  happens  to  be  installed. 
Direct  hydraulic  operation  is  the  best  if  pressure  water 
is  available.  But  failing  that,  either  steam  or  electricity 
are  quite  suitable.  The  latter  is  now  predominant. 
Some  cupolas  have  bucket  elevation,  and  transportation 
bucket  gantries. 

Trolleys  on  tracks  for  transportation  of  materials, 
boxes,  and  castings  are  simply  pulled  or  pushed  by 
hand.  In  rare  instances  light  locomotives  are  employed 
in  extensive  foundries. 

Machinery  for  the  preparation  of  materials  includes 
pig  breakers,  sand  grinders,  sand  sifters  and  mixers,  coal 
mills,  and  loam  mills.  The  best  arrangement  for  these  is 
that  of  short  lengths  of  countershaft,  motor-driven,  with 
fast  and  loose  pulleys  to  throw  any  machine  into  or  out 
of  action. 

Machinery  for  making  moulds  includes  chiefly  the 
various  moulding  machines,  and  then  all  subsidiary  con- 
veying systems,  which,  however,  are  used  only  in  shops 
where  the  output  is  large,  and  where  power  is  available. 
The  employment  of  a  large  installation  of  moulding  ma- 
chines need  not,  and  often  does  not,  involve  a  power 
plant,  for  the  majority  in  use  are  still  hand-operated. 
Patterns  on  machines  of  large  dimensions  can  be  dealt 
with  thus,  so  nicely  are  heavy  parts  counterbalanced, 
and  combinations  of  levers  devised'.  Hand  ramming  and 
pressing  is  also  more  common  than  power  ramming. 


90  PRACTICAL  IRON  FOUNDING 

When  power  is  used  it  is  chiefly  compressed  air  in  this 
country,  and  hydraulic  power  in  Germany. 

Machinery  for  cleaning  castings  includes  tumbling 
barrels,  sprue  cutters,  pneumatic  chisels,  cold  saws, 
emery  grinders,  and  sand-blasting  apparatus.  All  ex- 
cept the  last,  and  the  pneumatic  chisels,  which  are 
operated  by  compressed  air,  are  usually  belt-driven. 
The  countershaft  used  can  be  driven  by  a  steam-engine 
or  electric  motor.  The  direct  motor-driven  unit  is,  how- 
ever, gradually  coming  into  favour. 

In  the  foregoing  remarks  the  foundry  has  been  re- 
garded as  an  isolated  unit.  But  very  often  it  is  one  de- 
partment among  several  of  equal  importance  in  a  great 
engineering  works,  and  then  the  question  of  power  is  one 
which  embraces  the  works  as  a  whole.  In  such  a  case 
one  large  power  house  may  supply  electric  current  to  all 
the  shops,  where  it  is  taken  up  by  motors  located  as 
seems  most  desirable. 

The  large  works  also  is  favourable  to  the  best  possible 
adaptabilities  of  power,  because  not  only  electricity,  but 
also  hydraulic  and  pneumatic  plants  are,  of  necessity, 
installed.  The  boiler  shop  must  possess  the  last  two.  A 
stamping  shop  must  have  either  hydraulic  or  steam  or 
pneumatic  power,  often  two  of  them  if  heavy  and  light 
work  are  both  being  carried  on.  In  such  works  the 
foundry  will  be  highly  favoured  in  being  able  to  utilize 
the  best  possible  agents  for  its  various  services. 

Pleating  and  ventilation. — The  heating  and  ventilation 
of  foundries  have  too  often  been  neglected.  Modern 
buildings  are  usually  lofty,  the  areas  are  large,  and  large 
end  doors,  which  are  frequently  opened,  are  essential; 
and  these  conditions,  with  louvre  ventilation  in  the  roof, 
or  alternatively  swinging  sashes,  are  frequently  sufficient 


THE  SHOPS,  AND  THEIR  EQUIPMENT        91 

in  foundries  of  large  dimensions,  such  as  those  com- 
prising two  or  three  adjacent  bays.  Hence,  compara- 
tively few  foundries  have  provision  either  for  ventilation 
or  for  heating,  where  the  temperature  in  the  coldest 
weather  seldom  drops  lower  than  about  18  degrees  or  20 
degrees  Fahr.,  nor  remains  long  at  that.  In  the  northern 
United  States  and  Canada,  where  temperature  is  fre- 
quently a  good  way  below  zero  for  long  periods,  warming 
is  imperative,  and  ventilation  is  made  a  part  of  the 
system. 

The  plenum  system,  using  a  blower  circulating  cold 
air  on  the  outsides  of  banks  of  steam  pipes  which  con- 
stitute a  heater,  and  discharging  it  through  ducts  within 
the  building  just  above  head  room,  is  the  ideal  system. 
The  temperature  within  the  building  depends  on  numer- 
ous conditions  which  have  to  be  weighed  carefully,  such 
as  cubic  capacity,  amount  of  glass,  frequency  of  change, 
difference  between  the  outside  and  inside  temperatures 
required,  the  latter  being  usually  in  the  winter  50  degrees 
to  55  degrees  Fahr.  for  foundries.  Thence  the  tempera- 
ture to  be  imparted  to  the  air  at  the  heater,  the  size  and 
number  of  revolutions  of  the  blower,  the  sizes  of  pipes 
and  ducts  and  their  numbers  are  calculated,  being  the 
work  of  engineers  who  make  this  a  specialty. 

Small  steel  converters. — Steel  castings  are  now  used 
instead  of  those  of  iron  for  so  many  purposes  where 
lightness  has  to  be  sought,  as  well  as  strength,  that  a 
steel  foundry  has  become  a  frequent  annexe  to  the  iron 
foundry.  The  steel  firms  can  supply  castings,  but  delays 
and  expense  are  lessened  when  the  iron  foundries  make 
such  steel  castings  as  are  required  for  their  own  use. 

This  practice  has  been  fostered  and  developed  by  the 
growth  of  the  baby  or  small  steel  converters,  the  Tro- 


92  PRACTICAL  IRON  FOUNDING 

penas  being  generally  used.  The  choice  lies  between 
these  small  converters  and  the  small  open-hearth  furnace, 
since  the  ordinary  large  converters  handle  quantities  of 
metal  too  great  for  the  small  steel  foundry.  Moreover, 
the  grade  of  metal  is  not  so  easily  controlled  as  is  that 
in  the  small  converter  or  the  open-hearth  furnace. 

A  good  deal  might  be  said  in  favour  of  each  system. 
The  baby  converter  requires  a  rather  large  plant,  as  the 
metal  has  to  be  melted  in  a  separate  cupola  first,  and  a 
turning  or  tilting  gear,  power-operated,  is  essential.  The 
open-hearth  furnace  requires  no  such  aids,  but  it  must 
have  regenerators. 

On  the  whole,  it  appears  that  the  small  converter 
plant  is  being  installed  very  extensively  on  the  ground  of 
its  great  utility  in  small  castings  made  in  small  quan- 
tities, articles  which  have  previously  been  forged,  or 
made  in  malleable  cast  iron,  or  in  one  of  the  bronzes,  or 
in  cast  steel  in  the  regular  foundries.  Quantities  much 
smaller  than  the  contents  of  even  a  small  open-hearth 
furnace  can  be  melted  in  these  converters.  There  are, 
moreover,  considerable  numbers  of  small,  self-contained 
melting  furnaces  suitable  either  for  steel  or  the  bronzes, 
furnaces  of  tilting  type  and  having  blast  pipes,  as  the 
Schwartz  and  others.  These  are  extremely  simple,  more 
so  than  the  baby  Bessemer  designs  and  therefore  adapted 
to  conditions  which  might  not  admit  of  the  laying  down 
of  such  a  plant. 


CHAPTER  VI 

MOULDING  BOXES  AND  TOOLS 

FLASKS  or  moulding  boxes  are  employed  for  enclosing 
either  in  part  or  entirely  all  moulds  excepting  those 
which  are  made  in  open  sand.  The  lower  portion  of  a 
mould  may  be  in  the  sand  of  the  floor,  and  its  upper 
portion  in  a  flask.  Or  the  entire  mould  may  be  contained 
in  flasks  above  the  level  of  the  floor  sand. 

The  upper  portion  of  a  covered-in  mould  is  termed  the 
top  or  cope,  and  the  flask  corresponding  therewith  is  also 
termed  the  cope,  or  often  the  top  part.  The  flask  in  the 
bottom,  or  that  which  lies  on  the  floor,  is  called  the  dray, 
or  bottom  part.  If  there  is  a  central  flask,  that  is  named 
the  middle  or  middle  part.  These  are  shown  in  Figs.  29 
to  31.  In  this  group,  Fig.  29  is  a  cope,  Fig.  30  a  drag 
or  bottom,  and  Fig.  31  a  middle  part. 

It  follows  from  a  consideration  of  the  dbvious  functions 
of  flasks  that  they  must  fulfil  these  main  conditions — 
they  must  be  rigid  and  strong  enough  to  retain  their 
enclosed  sand  without  risk  of  a  drop-out  occurring,  and 
their  joints  and  fittings  must  be  coincident,  so  that  after 
the  withdrawal  of  the  pattern  they  shall  be  returned  to 
the  precise  position  for  casting  which  they  occupied 
during  ramming  up. 

Eigidity  and  strength  are  obtained  by  making  the 
flasks  of  cast  iron  of  sufficient  thickness.  Occasionally 
they  are  made  in  wood,  this  being  a  common  practice  in 

93 


94  PRACTICAL  IRON  FOUNDING 

the  United  States  and  Canada,  but  the  general  practice 
here,  and  by  far  the  better,  is  to  use  cast  iron.  The  evils 
of  a  weak  and  flimsy  flask  are,  springing  during  the  pro- 
cess of  turning  over  and  of  lifting,  causing  fracture  of 
the  sand  to  take  place,  and  portions  to  fall  out;  and 
springing  or  straining  of  the  cope  at  the  time  of  casting, 
producing  a  thickening  of  the  metal  over  the  strained 


FIG.  29.— A  COPE. 

area.     A  flask  should  not  be  excessively  heavy,  but  at 
least  it  requires  to  be  strong  and  rigid. 

Various  devices  are  adopted  in  order  to  ensure  the  re- 
tention of  the  contents  of  flasks.  Chief  among  these  are 
the  bars  or  stays  by  which  they  are  bridged,  A l  A l  in 
Figs.  29  and  30.  These  are  ribs  of  metal  usually  cast 
with  the  frames,  though  sometimes  bolted  therein,  to  be 


MOULDING  BOXES  AND  TOOLS 


95 


detachable  therefrom.  They  are  arranged  for  the  most 
part  at  equi-distant  intervals.  Their  forms  differ.  Thus 
the  typical  bars  for  bottom  or  drag  flasks  are  flat, 
Fig.  30,  A1,  their  function  being  the  retention  of  the 
sand  which  lies  thereon,  and  which  but  for  the  bars 
would  mingle  with  the  sand  on  the  floor.  Only  in  the 
case  of  special  flasks,  as  for  example  those  used  for  pipes, 


H 


«• 


t» 


FIG.  30.— A  DRAG. 

columns,  and  for  repetitive  work  (Figs.  32  to  34)  in 
which  the  bars  follow  the  contour  of  the  pattern,  is  this 
practice  departed  from.  The  bars  in  the  cope  (Fig.  29, 
A  l)  are  made  on  an  essentially  different  plan.  Here  they 
are  never  flat,  but  always  vertical,  being  rather  of  the 
nature  of  ribs  than  of  bars.  For^general  work  they  are 
parallel,  as  in  Fig.  29,  but  for  special  work  their  lower 
edges  are  cut  to  the  contour  of  the  pattern  which  they 


96 


PRACTICAL  IRON  FOUNDING 


cover  (Figs.  32  to  34),  but  kept  to  a  distance  of  1  in. 
or  -J  in.  away  from  the  patterns.  They  are  always  cham- 
fered also,  Fig.  29,  because  if  left  flat,  the  sand  lying 
immediately  underneath  the  bars  would  be  insufficiently 
rammed.  Being  chamfered  almost  to  a  knife-edge,  the 
full  pressure  of  the  rammer  is  exerted  immediately  un- 
derneath the  bars,  as  elsewhere. 


-   D 


w 


c' 


FIG.  31. — A  MIDDLE. 

There  are  no  stays  in  middle  parts  excepting  for  some 
special  work.  Middles  for  general  work  are  always  left 
clear  of  bars,  as  in  Fig.  31,  because  they  have  usually 
to  contain  a  zone  of  sand  only,  the  central  portions 
being  open.  To  retain  this  zone  of  sand,  rods  and  lifters 
are  employed,  the  function  and  mode  of  use  of  which  are 
described  at  p.  147.  Lifters  are  also  employed  in  the 
cope.  A  rib  is  cast  around  the  inner  bottom  edge  of  a 


FIG.  23 
HEAVY  LADLE 


PLATE  IV 


FIG.  24 
CARRIAGE  LADLE 


FIG.  25 

BOGIE  CARRIAGE 
LADLE 


See  v. 


[Facing  p.  96 


JL. 


€ 


f 


98  PRACTICAL  IEON  FOUNDING 

middle,  Fig.  31,  B,  to  assist  in  the  retention  of  the 
sand,  and  also  as  a  convenient  support  for  the  rods 
which  help  to  carry  the  lifters  and  the  sand. 

Flasks  are  always  cast  with  a  very  rough  skin,  the 
better  to  retain  their  contents.  They  are  frequently 
made  in  open  moulds,  no  blackening  is  used,  and  their 
inner  faces  are  often  purposely  hatched  up  to  increase 
their  adhesive  power. 

The  coincidence  of  the  joints  of  moulds  is  effected  dif- 
ferently in  the  case  of  work  which  is  bedded  in,  than  in 
that  which  is  turned  over.  Thus,  the  mould  being  bedded 
mainly  in  the  floor,  the  cope  is  set  by  means  of  stakes  of 
wood  or  iron;  but  being  turned  over,  the  flasks  are  fitted 
with  pins. 

In  the  first  method,  one  example  of  which  is  shown  on 
pp.  165  to  169,  the  pattern  having  been  bedded  in,  and 
rammed  up  as  far  as  the  joint  face,  parting  sand  is 
strewn  thereon,  and  the  cope  lowered  into  its  position 
for  ramming.  Before  being  rammed,  however,  its  per- 
manent place  is  definitely  fixed  by  the  stakes,  which  are 
driven  deeply  down  into  the  sand  of  the  floor  alongside 
of  the  lugs,  Fig.  29,  E,  E,  or  other  projections  standing 
from  its  sides.  See  also  p.  174,  Fig.  97,  D.  Being  then 
rammed,  and  afterwards  lifted  off  for  withdrawal  of  the 
pattern,  and  cleaning  and  finishing  of  the  mould,  it  is 
returned  and  guided  to  its  original  position  by  the  stakes 
in  the  floor. 

In  the  second  method  the  lugs  cast  upon  the  sides 
of  the  flask  parts  have  holes  drilled  to  correspond 
with  each  other,  and  long  turned  pins  are  bolted  into 
the  lugs  which  are  lowermost,  and  pass  into  the  corre- 
sponding holes  in  the  lugs  above.  The  more  care  which 
is  taken  with  the  fitting  up  of  these  lugs,  the  more  accur- 


MOULDING  BOXES  AND  TOOLS 


99 


ately  will  the  boxes  and  consequently  the  mould  joints 
correspond.  The  length  of  the  pins  should  be  settled 
with  reference  to  the  nature  of  the  work.  In  any  case 
the  pins  should  enter  their  holes  before  any  portions  of 
the  opposite  mould  faces  come  into  contact.  Unless  the 
pins  guide  the  closing  mould  there  is  always  danger  of  a 
crush  of  the  sand  occurring.  In  shallow  flat  work, 
therefore,  the  pins  may  measure  no  more  than  3  in.  or 
4  in.  in  length.  But  in  work  having  deep  vertical  or 


FIG.    34. — SECTION    OF 
COLUMN  Box  (FiG.  33). 


FIG.  35.— PIN  AND 
COTTAR. 


diagonal  joints  the  pins  may  require  to  be  8  in.  or  even 
10  in.  long.  The  practice  is  usually  to  make  the  pins 
point  upwards.  Thus,  in  Figs.  29,  30,  and  31,  the  parts  of 
the  flasks  are  represented  in  their  correct  relations  for 
super-position  at  the  time  of  final  closing  of  the  mould. 
The  drag  (Fig.  30)  has  its  pins  G,  G,  pointing  upwards 
ready  to  enter  into  the  lugs  C\  C\  of  the  middle  (Fig.  31). 
The  pins  F,  F,  of  Fig.  31  also  point  upwards  to  enter 
into  the  lugs  E,  E,  of  the  cope  (Fig.  29). 

The  best  method  of  securing  the  pins  is  with  cottars 
(Fig.  35);    sometimes,  however,   in  deep   moulds    cast 


100  PRACTICAL  IRON  FOUNDING 

vertically,  the  pins  are  short,  and  the  ends  are  screwed 
and  the  tightening  is  effected  with  nuts. 

When  flasks  are  retained  in  position  with  stakes,  cot- 
taring  or  screwing  cannot  of  course  be  effected,  yet  great 
counter  pressure  is  necessary  to  prevent  a  cope  from 
being  strained  and  lifted  at  the  time  of  pouring.  Weights 
are  therefore  employed  for  this  purpose,  the  amount  re- 
quired being  estimated  roughly  according  to  the  area  of 
the  mould,  and  its  depth  from  the  pouring  basin. 

If  the  contact  area  of  a  cope  measures  four  feet 
square,  and  the  height  of  the  pouring  basin  is  one  foot 
above  it,  the  amount  of  weight  required  by  calculation 
to  keep  it  down,  including  its  own  weight,  will  be 
48"  x  48"  x  12"  x  -263  lb.,  the  latter  being  the  weight 
of  a  cubic  inch  of  iron.  This  would  give  7,121  lb.  re- 
quired for  loading,  or  over  3|  tons.  Actually,  a  moulder 
seldom  attempts  to  calculate  the  weight  necessary  to 
load  a  flask  properly,  because  so  many  other  conditions 
have  to  be  considered  besides  the  simple  laws  of  hydro- 
statics. There  is  a  good  deal  of  pressure  due  to  momen- 
tum to  be  taken  into  account.  Metal  poured  directly 
into  the  mould  will  exercise  more  straining  action  than 
that  led  in  at  the  side.  Rapid  pouring  again  will  cause 
more  momentum  than  slow  pouring.  Hot  metal  will  in- 
duce more  strain  than  dead  metal.  Risers  relieve  strain. 
The  moulder,  therefore,  loads  according  to  the  best  of  his 
experience  and  judgment,  and  not  by  calculation  merely, 
which  alone  would  often  lead  him  astray. 

There  are  numerous  minor  attachments  to  flasks,  used 
both  for  general  and  for  special  purposes.  All  flasks  re- 
quire to  be  turned  over,  either  for  ramming,  or  for  clean- 
ing up  of  the  mould.  For  this  purpose  handles  are 
provided  in  the  small  flasks,  and  middles,  Fig.  31,  F,  and 


MOULDING  BOXES  Am  TOVVS",*.  |\5  tyl 

swivels  in  larger  ones,  Fig.  30,  H,  and  Figs.  32  and  33. 
The  swivels  rest  in  slings  depending  from  a  cross  beam, 
the  beam  being  suspended  from  the  crane  the  while. 
Since  handles  and  swivels  require  to  be  very  firmly 
secured  in  place,  they  are  not  only  made  of  wrought  iron 
and  cast  in  position,  but  the  metal  is  increased  around 
that  portion  which  is  cast  in,  as  shown  in  Figs.  29,  30, 
31,  32,  and  33. 

There  are  other  attachments,  as  handles,  Fig.  33,  B,  B, 
for  turning  over  flasks  which  are  too  long  to  be  slung  in 
the  crane  in  the  manner  just  noted,  and  for  lowering 
them  into  the  foundry  pit  for  vertical  casts.  There  are 
also  flanges,  C,  C,  in  the  same  figure,  for  the  attachment 
of  back  plates,  that  is,  plates  of  cast  iron  bolted  to  the 
backs  of  deep  flasks  which  have  to  be  poured  vertically, 
and  which  are  subject,  as  all  deep  moulds  are,  to  enorm- 
ous liquid  pressure.  The  back  plates  prevent  all  risk  of 
the  pressure  forcing  out  the  molten  metal,  and  so  pro- 
ducing a  waster  casting. 

The  forms  of  flasks  vary  widely,  being  rectangular, 
both  square  and  oblong,  and  having  ordinary,  or  special 
bars.  Or,  cope  and  drag  may  be  precisely  alike,  and 
bars  be  alike  in  each,  as  in  Figs.  32  and  33,  which  repre- 
sent pipe  and  column  boxes,  Fig.  32  being  for  pipes,  and 
Fig.  33  for  columns.  The  sides  are  bevelled  in  Fig.  32,  to 
economize  the  sand,  and  time  spent  in  ramming,  a  con- 
sideration when  large  numbers  of  casts  are  required. 
In  Fig.  32,  and  Figs.  33  and  34  the  holes  D  in  the  ends 
are  for  the  purpose  of  allowing  the  ends  of  the  core 
bars  to  project  through.  Flasks  are  also  circular  for  cir- 
cular work,  or  of  irregular  and  unsymrnetrical  outlines  to 
suit  work  of  special  character.  In  jobbing  shops,  flasks 
will  be  sometimes  fitted  with  interchangeable  bars  bolted 


1Q2 


PRACTICAL  IRON  FOUNDING 


in  place.  Pockets  also  are  often  fitted  at  the  ends,  which 
are  then  bolted  on,  to  be  removable,  the  object  being  to 
increase  the  length  of  the  flask.  Sometimes  pockets  are 
bolted  on  the  sides  to  take  branches,  and  holes  are  cut 


FIG.  36. — WOODEN  SNAP  FLASK. 

through  the  flask  sides  next  the  pockets.  In  all  these 
cases  the  question  to  be  decided  is  one  of  relative  cost,  as 
between  the  expense  of  the  alterations,  and  that  of  a  new 
flask.  Flasks  cost  little  for  making,  and  the  metal  is 
always  worth  nearly  its  first  value  for  re-melting.  The 


MOULDING  BOXES  AND  TOOLS 


103 


dimensions  of  flasks  will  range  from  6  in.  to  12'  0"  square, 
or  from  I'  6"  to  20'  0"  long,  if  of  oblong  form. 

Snap  flasks. — Figs.  86  and  37  show  a  wooden  snap 
flask,  made  up"  to  about  14  in.  square,  with  pins  of  tri- 
angular section,  having  provision  for  taking-up  wear. 


FIG.  37.  —  WOODEN  SNAP  FLASK. 


These  are  made  of  birch  or  other  suitable  hard  wood,  1  in. 
to  1^  in.  thick,  by  3  in.  deep,  in  standard  sizes.  As  no 
bars  or  stays  can  be  used,  each  side  has  two  concave 
recesses  cut  longitudinally,  so  that  the  boxes  can  be 
lifted  without  risk  of  the  sand  falling  out.  The  fast 
corners  are  bonded  with  I  in.  sheet  iron  running  the 
whole  depth.  The  hinge  is  made  with  J  in.  straps.  The 


104 


PRACTICAL  IRON  FOUNDING 


snap  at  the  opposite  corner  is  of  the  latch  type  (compare 
with  Fig.  38),  and  the  latch  cannot  he  locked  in  place 
unless  the  corners  are  in  absolutely  close  contact. 
This  fitting  is  of  brass,  to  avoid  rusting  up.  The  pins, 
which  are  also  of  brass  for  the  same  reason,  are  seen  in 
Figs.  36  and  38.  The  pin  is  cast  on  an  angle  bracket  that 
is  screwed  to  the  side  of  the  top  box,  and  fits  through  a 
a  hole  in  another  angle  bracket  on  the  bottom  box.  This 
bracket  is  made  in  two  pieces,  one  of  which  is  screwed 
to  the  box  side,  and  the  other  attached  to  the  horizontal 


FIG.  38. — DETAILS  OF  SNAP  FLASK. 

portion  with  two  set  bolts,  over  which  slot  holes  in  the 
adjustable  piece  slide,  permitting  the  taking  up  of  wear. 

The  pattern  plate,  Figs.  39  and  40,  has  triangular 
holes  to  receive  the  pins,  and  lugs  on  opposite  corners 
for  the  purpose  of  rapping  and  lifting  it  by.  The  plate  is 
of  cast  iron,  \  inch  thick,  planed  on  both  sides.  That 
shown  in  the  figure  has  pattern  parts  on  both  sides,  and 
ingates  and  runners  on  the  top,  Fig.  40.  Presser  boards 
for  top  and  bottom,  Fig.  41,  stiffened  with  battens,  fit 
freely  inside  the  flask  parts. 

A  man  and  a  boy  operate  a  machine  and  set  of  moulds 


MOULDING  BOXES  AND  TOOLS  105 

thus :  The  sand  being  mixed  and  damped  and  thrown  in  a 
heap  at  the  side  of  the  machine,  the  man  commences  work 
by  placing  the  complete  flask  on  the  machine  upside  down 
—that  is,  with  the  pins  pointing  downwards — and  lifts 
off  the  upper  part,  Fig.  36  (the  bottom  part  in  the  com- 
pletely-rammed mould).  The  pattern  plate  is  next  laid 
on  the  joint  face  of  the  box  part — with  the  deepest  por- 
tion of  the  patterns  facing  upwards — and  the  upper  part 
is  replaced  over  the  plate,  the  pins  passing  therefore 
through  the  plate  and  the  lower  one.  The  lad  now  throws 
sand  into  the  box  from  the  heap,  while  the  man  tucks 
the  sand  round  the  patterns  with  his  hands.  When  the 
box  part  is  filled,  the  sand  is  strickled  off  level,  and  the 
bottom  board,  or  carrying-down  board,  Fig,  41,  is  laid 
upon  the  strickled  surface. 

During  this  time  the  table  or  platen  has  been  standing 
out  clear  of  the  presser  head,  but  now  a  catch  on  the 
right-hand  side  of  the  machine,  which  has  hitherto  re- 
tained the  table  in  place,  is  released,  and  the  table  is 
moved  to  bring  the  mould  under  the  presser  head.  The 
lever  is  pulled  sharply  once  or  twice,  raising  the  table 
and  bringing  the  press  board  in  contact  with  the  head, 
compressing  the  sand,  and  sending  the  presser  board 
between  the  box  sides  to  a  depth  of  from  f  in.  to  1  in. 

Eeleasing  now  the  lever  and  the  catch,  the  table  moves 
forward  and  remains  locked  in  a  slot,  bringing  the  box 
clear  of  the  head.  The  man  now  turns  it  over,  and  the 
same  operation  of  shovelling  in,  tucking,  and  strickling 
off  the  sand  is  gone  through.  The  second  presser  board, 
now  put  on,  carries  the  pattern  cup  for  the  ingate,  which 
comes  plumb  over  the  ingate  boss  on  the  pattern  plate. 
The  same  operation  of  running  the  table  back  and  press- 
ing is  repeated. 


106 


PRACTICAL  IRON  FOUNDING 


The  table  is  next  drawn  out,  the  pressing  board  lifted 
off,  leaving  the  impression  of  the  pouring  cup,  which  is 
now  connected  to  the  boss  beneath  by  removing  the  sand 
with  a  tubular  cutter.  The  lad  next  raps  the  projecting 
lugs  at  the  corners  of  the  pattern  plate,  and  the  man 
lifts  the  top  part  of  the  flask  and  places  it  on  edge  on  a 
stand  at  the  left-hand  side  of  the  machine.  The  lad  raps 
the  plate  on  the  top  face,  and  the  man  draws  it,  together 


FIG.  39. — PATTERN  PLATE  FOR  SNAP  FLASK. 

with  the  lower  sections  of  the  patterns,  from  the  bottom 
part.  The  lugs,  with  their  well-fitting  pins,  enable  the 
man  to  give  a  steady  perpendicular  lift  until  the  patterns 
are  quite  clear  of  the  mould. 

At  the  next  stage  the  halves  of  the  moulds  are  closed, 
standing  on  the  bottom  press  board.  The  catches  or 
snaps  at  the  corners  are  released,  and  the  flasks  are 
opened  on  their  hinges  away  from  the  mould,  which  is 
left  standing  on  the  board.  This  is  then  carried  away 


MOULDING  BOXES  AND  TOOLS 


107 


bodily  and  laid  on  the  floor,  and  other  similar  moulds 
made,  so  that  instead  of  a  separate  flask  for  each  mould, 
one  flask  suffices,  and  as  many  bottom  boards  as  there 
are  moulds  in  a  day's  work. 

As  there  is  no  cottaring  of  pins  done,  the  moulds  are 
kept  closed  by  flat  weights — one  to  each  mould.  Each 
covers  the  area  of  the  mould  and  has  a  centre  hole 
through  which  pouring  is  done.  They  are  lifted  by 


FIG.  40. — PATTERN  PLATE  FOR  SNAP  FLASK. 

wrought-iron  eyes  cast  in  at  opposite  ends.  About  six 
weights  suffice,  because  they  are  being  moved  from  the 
first  moulds  poured  as  the  pouring  is  being  done  on  the 
fifth  or  sixth.  The  lad  does  this  as  the  man  pours. 

With  regard  to  the  effect  of  the  pressure  of  metal  on 
moulds  unsupported  by  flasks,  no  difficulty  occurs  unless 
the  moulds  contain  rather  heavy  castings.  In  cases  where 
their  weight  does  not  exceed  about  12  Ib.  there  is  no 
trouble.  In  heavier  ones,  up  to  about  28  Ib.  weight,  the 


108 


PRACTICAL  IRON  FOUNDING 


moulds  are  enclosed  with  sheet-iron  binders,  which  are 
slipped  over  the  moulds.  As  light  castings  form  the 
staple  in  many  foundries,  the  saving  in  cost  and  storage 
room  for  flasks  mounts  up.  Actually  a  man  and  a  boy 
can  put  down  from  150  to  200  boxes  in  a  day,  besides 


nil 

FIG.  41. — PRESSER  BOARD. 

getting  the  sand  ready,  coring  when  required,  casting, 
and  knocking  out  the  castings. 

The  illustration,  Fig.  42,  is  drawn  to  give  the  relation 
of  the  box  parts  to  the  pattern  plate,  shown  between 
them,  and  the  top  and  bottom  presser  boards. 

a      ^i      m 


FIG.  42. — SHOWS  RELATION  OF  Box  PARTS  TO  PATTERN 
PLATE  AND  BOARDS. 

Tools. — The  small  tools  used  by  moulders,  and  mostly 
provided  by  themselves,  though  not  numerous,  are  very 
characteristic  of  the  work  done.  Foremost  among  them 
is  the  rammer,  varieties  of  which  are  shown  in  Fig.  43, 
A  being  the  usual  form  of  pegging  rammer,  B  another 
form,  C  and  D  flat  rammers.  A  and  B  are  employed  for 


MOV L DING  BOXES  AND  TOOLS 


109 


consolidating  the  sand  in  narrow  spaces,  and  generally 
for  all  the  earlier  stages  of  ramming,  C  and  D  being 
used  only  for  final  flat  ramming,  or  finishing  over  of 
surfaces.  E  shows  the  manner  in  which  the  flat  rammer 
is  handled,  a  wedge  at  the  lower  end  being  driven  home 
by  the  forcing  down  of  the  handle  into  the  socket  of  the 
rammer  head. 


FIG.  43. — EAMMERS. 

Vent  wires  are  shown  at  Fig.  44,  B  being  a  small 
pricker  or  piercer,  as  it  is  sometimes  called,  the  other, 
A,  being  larger  and  requiring  considerable  force  to  use. 
The  smaller  wire,  which  may  be  from  ^  in.  to  A  in.  in 
diameter  is  employed  for  piercing  the  sand  in  the  imme- 
diate vicinity  of  the  pattern  with  innumerable  holes,  all 
leading  into  larger  vents,  or  into  the  gutters  in  the  joint 
faces.  The  larger  wires  will  range  from  ^  in.  to  f  in.  and 


110 


PRACTICAL  IRON  FOUNDING 


are  used  for  venting  down  to  cinder  beds  underneath 
flasks,  and  around  the  edges  of  deep  patterns,  bringing 
off  the  vents  from  the  smaller  channels. 

The  trowels  (Fig.  45)   are    in  perpetual  request    for 


FIG.  44. — VENT  WIRES. 


FIG.  45. — TROWELS. 


smoothing  or  sleeking  the  surfaces  of  moulds,  for  spread- 
ing and  smoothing  the  blackening,  and  for  mending  up 
broken  sections  of  moulds.  They  are  also  employed  for 
finning  joints  of  dry  sand  moulds,  for  marking  lines  on 


FIG.  46. — CLEANER. 

sand  faces,  and  are  improvised  for  many  purposes  beyond 
those  for  which  they  are  legitimately  designed.  A  is  the 
common  heart  shape,  D  the  square  trowel,  and  C  the 
combination,  or  heart  and  square  form. 

Fig.  46  is  a  cleaner,  a  tool  used  for  mending  up  and 


112  PRACTICAL  IRON  FOUNDING 

smoothing  the  deeper  portions  of  moulds  which  cannot 
be  reached  by  the  trowel. 

The  remaining  figures  (47)  illustrate  finishing  tools. 
A  is  a  square  corner  sleeker,  also  spelt  slicker,  or  slaker. 
B  is  a  similar  tool,  except  that  one  face  is  adapted  for 
sweeps,  hence  called  flange  corner  sleeker.  C  is  a  bead 
tool  or  smoother,  or  pipe  smoother,  for  smoothing  the  im- 
pressions of  beads  or  sweeps  of  that  section.  D  is  a 
liollow  bead.  E  is  a  spoon  tool.  F  is  a  square  or  flange 
bead.  G  is  a  bead  tool  curved  lengthwise.  H,  I,  J,  are 
flange  tools,  K,  K,  boss  tools.  L  is  a  Button  sleeker  or 
bacca  box  smoother.  M  an  oval  pipe  sleeker.  N  another 
pipe  sleeker.  These  tools,  with  a  rule  and  calipers,  com- 
plete the  private  kit  of  a  moulder. 

Other  aids. — The  general  appliances,  used  in  moulding, 
omitting  those  of  the  nature  of  machines,  and  those  not 
directly  employed  in  moulding,  are  shovels,  lamps, 
riddles,  sieves,  buckets,  water-cans,  bellows,  oil-cans. 
Shovels  are  used  for  sand-mixing  and  box-filling,  lamps 
for  throwing  light  into  the  darker  recesses  of  moulds; 
the  uses  of  riddles  and  sieves  have  been  described, 
p.  23;  buckets  and  water-cans  are  used  for  damping  sand 
and  swabbing  moulds,  bellows  for  blowing  away  parting 
sand  and  loose  particles  generally,  oil-cans  for  pouring 
oil  over  chaplets,  and  on  damped  corners  and  sections  of 
moulds  to  prevent  the  metal  from  bubbling  and  caus- 
ing scabs.  These  are  all  provided  by  the  firm  for 
general  use. 


CHAPTER  VII 

SHRINKAGE — CURVING — FRACTURES FAULTS 

THOUGH  the  laws  which  govern  shrinkage  and  curving  of 
castings  are  somewhat  obscure  and  uncertain,  yet  little 
difficulty  is  experienced  in  making  allowances  sufficiently 
exact  for  all  practical  purposes.  Curving,  however,  as  a 
rule  gives  greater  trouble  than  shrinkage. 

The  linear  shrinkage  of  all  ordinary  iron  castings  is  pretty 
constantly  Jin.  in  15  in.  If,  however,  a  casting  is  exception- 
ally light  a  rather  greater  allowance  should  be  made,  say 
Jin.  in  12  in.,  if  unusually  massive  a  smaller  allowance,  say 
|  in.  in  18  in.  or  20  in.,  and  in  the  case  of  a  very  massive 
solid  casting  the  shrinkage  appears  to  be  almost  nil  A 
casting  will  apparently  shrink  less  in  the  direction  of  its 
depth  than  in  that  of  its  length  or  breadth,  but  this  is 
apparent  rather  than  real,  for  a  very  deep  casting  will 
be  found  on  careful  measurement  to  have  shrunk  to  the 
normal  extent,  showing  that  the  apparent  diminution  in 
the  vertical  shrinkage  of  shallow  castings  is  due  to  second- 
ary causes,  chief  of  which  is  the  springing  or  straining 
upwards  of  the  cope  by  reason  of  liquid  pressure.  Cast- 
ings, the  central  portions  of  which  are  hollowed  with 
numerous  dried  sand  cores,  and  which  are  rendered 
rigid  by  ribs,  or  which  are  plated  over,  do  not,  as  a  rule, 
contract  so  much  as  those  in  which  shrinkage  is  unim- 
peded, as  for  example  in  those  cases  where  the  centre  is 
cored  with  green  sand,  or  when  metal  is  not  massed 

i 


114  PRACTICAL  IRON  FOUNDING 

heavily  about  the  centre.  Thus,  a  gear  wheel  with  arms 
will  shrink  less  than  a  mere  ring  of  teeth.  Hard  white 
iron  also  shrinks  much  more  than  the  soft  gray  kind — 
roughly,  twice  as  much — and  strong  mottled  iron  occu- 
pies a  position  about  midway  between  the  other  two. 
When,  therefore,  it  is  stated  that  the  shrinkage  of  iron 
equals  |  in.  in  15  in.,  that  is  given  as  a  good  average, 
£  in.  in  12  in.,  as  sometimes  stated,  is  not  correct  for 
ordinary  work,  but  only  so  for  the  lightest  castings,  for 
which  it  is  about  a  proper  average. 

Of  the  curving  of  castings  the  barest  summary  need 
be  given.  An  excess  of  metal  in  the  form  of  a  rib  on  one 
side  of  a  long  casting  invariably  induces  a  concave  cur- 
vature on  that  side,  the  concavity  increasing  with  the 
amount  of  disproportion.  Where  there  are  two  flanges 
of  unequal  thickness  in  a  long  girder  or  girder-like  casting, 
concavity  will  result  on  the  side  of  the  heavy  or  thick 
flange.  When,  in  a  column  or  pipe  the  metal  is  of  un- 
equal thickness,  the  casting  will  go  concave  on  the  side 
where  the  metal  is  thinnest — the  direction  of  curvature 
being  precisely  the  reverse  of  that  which  is  witnessed  in 
a  girder  or  a  ribbed  casting.  Both  sets  of  facts  are, 
however,  consistent  with  one  another.  The  explanation 
appears  to  be :  that  in  the  column  the  disproportion  in 
thickness  is  so  slight,  that  cooling,  and  the  initial  shrink- 
age, and  consequent  curving  of  the  thin  side  remains 
permanent,  while  in  the  case  of  the  girder,  though  the 
thin  flange  shrinks  and  curves  first,  yet  sufficient  heat  is 
transmitted  from  the  heavy  flange  through  the  web  to 
maintain  the  thin  flange  in  a  semi-plastic  condition. 
Cooling  slowly  therefore  under  restraint,  its  crystals 
remain  somewhat  large  and  its  texture  open,  and  its 
total  shrinkage  is  thereby-  diminished.  Finally,  the 


SHRINKAGE— CURVING— FRACTURES,  ETC.     115 

heavy  flange  shrinks  to  its  full  extent,  more  so  than 
the  thin  one,  the  shrinkage  of  which  has  been  delayed 
and  diminished.  The  heavy  flange  consequently  becomes 
concave,  pulling  the  thin  flange,  still  at  about  its  own 
temperature,  convex.  Figs.  48  to  51  show  typical  sec" 
tions,  which,  if  long  relatively  to  their  cross  sections, 
will  infallibly  become  concave  in  cooling  on  the  sides 
marked  .4.  This  curvature  is  termed  camber,  and  a 
pattern  is  cambered  to  the  precise  amount  by  which  its 
casting  is  expected  to  curve,  and  in  the  opposite  direction. 
It  is,  however,  only  possible  to  design  patterns  to  neu- 
tralize the  curvature  in  unsymmetrical  castings  by  much 


A 

FIG.  48.  FIG.  49.          FIG.  50.  FIG.  51. 

SECTIONS  LIABLE  TO  CURVE. 

observation  of  actual  cases,  experience,  and  very  often 
in  new  work,  some  tentative  measures  being  the  only 
guides;  all  depends  on  relative  proportions,  that  is  on 
length,  as  well  as  on  cross  section,  a  vital  point  which 
must  be  ever  borne  in  mind. 

The  Fracture  of  Castings. — Iron  castings  break  by 
reason  of  the  unequal  tension  which  occurs  between 
adjacent  parts.  As  a  mere  statement  this  seems  simple 
enough,  but  so  many  causes  contribute  to  such  a  result 
that  the  reasons  for  fracture  are  not  always  apparent. 

By  unequal  tension  is  understood  the  internal  stress 
which  is  set  up  by  the  skrinkage  of  metal  during  its 
cooling  down  after  pouring.  This  affects  castings  in  two 


116  PRACTICAL  IRON  FOUNDING 

ways,  one  being  that  which  results  from  the  arrange- 
ment of  the  crystals,  the  other  that  of  the  thick  and  thin 
sections  which  are  tied  together  in  close  proximity.  The 
problems  involved  in  these  two  cases  differ,  and  yet  they 
are  in  some  degree  related.  The  first  is  readily  under- 
stood both  in  theory  and  in  its  practical  applications: 
the  second  is  not  so  easy  of  recognition.  Castings  will 
sometimes  fracture  in  a  manner  which  is  not  readily 
explained,  as  in  frosty  weather,  though  even  then  the 
reasons  are  generally  traceable  to  a  neglect  of  the  two 
conditions  named  above,  crystallization,  and  the  proper 
proportioning. 

There  is  something  which  almost  savours  of  instinct 
possessed  by  the  man  who  is  able  to  design  castings  which, 
even  though  awkwardly  shaped,  will  not  fracture,  ft  is 
not  always  practicable  to  produce  ideal  designs  such  as  will 
meet  with  the  approval  of  the  moulder;  but  the  latter 
can  often  secure  safety  even  in  undesirable  shapes.  The 
drawing  office  should  always  keep  in  close  touch  with 
the  foundry  when  new  designs  are  being  got  out.  Wasters 
would  often  be  avoided  if  this  precaution  were  taken, 
apart  from  the  unnecessary  expense  which  is  frequently 
incurred  in  the  cost  of  moulding  shapes,  the  designs 
of  which  could  be  modified  without  detriment  to  the 
mechanism  of  which  they  form  a  portion. 

It  is  hardly  necessary  to  remark  that  crystallization 
explains  why  sharp  angles  are  or  should  be  avoided,  as 
far  as  possible,  in  castings.  In  chilled  castings  the 
planes  of  crystallization  are  most  apparent.  But  they 
always  exist  in  ordinary  gray  iron  castings,  and  the 
sharp  angles  which  occur  in  rectangular  shapes  (Fig.  52) 
invite  easy  fracture.  In  curved  outlines  (Fig.  53)  there 
are  no  sharp  planes  of  separation.  Hence  curved  designs 


SHRINKAGE— CURVING— FRACTURES,  ETC.     117 


are  not  only  more  graceful,  but  stronger  than  square 
ones,  and  the  larger  the  curves  the  better.  But  square 
designs,  with  a  small  radius,  combined  with  bracketings, 
are  also  strong.  But  the  bracketing  should  be  continuous 
with  the  main  body  of  metal,  and  not  take  the  form  of  a 
cross-tie,  which  is  weak.  Examples  of  the  latter  occur 
in  gratings  and  other  objects.  If  the  crossing-pieces  are 
of  slight  section,  and  the  surrounding  portions  are 
massive,  the  former  are  almost  certain  to  become  pulled 
away  from  the  latter  in  some  degree.  The  results  will 
be  similar  if  the  ties  are  of  large  section  and  the  sur- 


FIG.  52.  FIG.  53. 

CRYSTALLIZATION  IN  CASTINGS. 

roundings  slight.  In  the  direct  pulls  exercised  by  shrink- 
ages at  right-angles,  the  lines  of  cleavage  of  the  crystals 
will  be  weak  sections  that  will  readily  part  in  two.  But 
if  a  large  flowing  curve  is  inserted,  to  form  the  union, 
the  shrinkage  will  be  distributed  around  that,  and  the 
section  itself  will  be  strengthened,  because  there  will  be 
no  abrupt  lines  of  crystallization  present. 

But  a  limit  soon  comes  to  the  strength  which  a  proper 
disposition  of  the  crystals  affords,  a  limit  at  which 
unequal  shrinkage  will  tear  contiguous  sections  asunder. 
Here  a  considerable  experience  becomes  necessary  to 
enable  a  man  to  design  forms  that  will  not  fracture. 
The  presence  of  thick  and  thin  sections  in  close  proximity 


118  PRACTICAL  IRON  FOUNDING 

will  not  alone  induce  fracture.  The  safe  condition  is  that 
they  are  free  to  shrink  in  on  themselves.  They  will  only 
fracture  if  they  are  tied,  and  bound  fast,  so  that  their 
shrinkage  is  thereby  prevented.  This  will  happen  if  the 
casting  in  itself  is  of  improper  form,  or  if,  though  cor- 
rectly proportioned,  it  is  prevented  from  shrinkage  in  its 
mould.  The  first  is,  of  course,  by  far  the  most  frequent, 
but  the  latter  is  rather  common. 

A  good  object  lesson  in  the  causes  which  produce 
fracture  is  the  familiar  cast-iron  belt-pulley.  This 
is  safe  if  properly  designed,  excepting  at  excessive 
rates  of  revolution;  but,  if  disproportioned,  it  will 
fracture  in  the  mould  in  cooling,  or  afterwards,  when 
being  turned,  or  when  being  keywayed,  or  while  working, 
all  these  being  not  uncommon  mishaps.  The  reason 
why  pulleys  in  particular  are  so  sensitive  is  because  the 
metal  is  so  slight  that  it  cools  more  rapidly  in  rim  and 
arms  than  in  the  boss.  The  boss  is  the  chief  source  of 
danger.  A  slight  difference  in  its  thickness  makes  the 
difference  between  safety  and  risk.  Thick  bosses,  there- 
fore, should  never  be  used  on  light  pulleys.  The  extra 
thickness  required  round  the  keyway  should  be  added 
as  a  keyway  boss.  If  a  boss  is  very  long  it  is  also 
risky,  and  then  the  bore  should  be  enlarged — chambered 
out,  at  the  central  portion.  And  if  the  recessed  pulley  is 
a  loose  one  it  may  be  bushed  right  through,  covering  up 
the  chamber  or  recess. 

But,  after  the  boss,  a  rim  too  thick  causes  risk  of 
fracture.  For  if  the  rim  is  thin  it  will  become  broken 
and  pulled  inwards  by  the  fracture  of  one  arm  or  more. 
If,  on  the  other  hand,  it  is  thick,  it  will  break  off  an  arm 
or  arms.  For  this  reason  again,  the  allowance  for 
turning  must  not  be  excessive  on  a  rim  already  properly 


SHRINKAGE— CURVING— FRACTURES,  ETC.     119 

proportioned,  else  the  pulley  may  fracture  in  cooling. 
And  if  a  rim  is  cast  of  medium  thickness,  even  though 
it  may  not  fracture  in  the  mould,  it  is  liable  to  do 
so  while  being  turned,  when  it  arrives  at  that  stage 
where  its  strength  is  overcome  by  the  tension  of  the 
arms. 

Lastly,  the  arms  may  be  too  light,  in  which  case  they 
will  fracture  under  the  pull  exercised  by  the  cooling 
boss.  Or  they  may  be  too  heavy,  and  cause  fracture  of 
the  rim.  In  belt-pulleys,  therefore,  the  proportioning 
of  each  part  must  be  nicely  adjusted  if  fracture  is  to  be 
avoided. 

And  what  occurs  in  a  pronounced  degree  in  pulleys 
happens  in  a  less  marked  extent  in  toothed  wheels,  in 
the  centre  castings  of  crane  beds,  and  in  the  castings  for 
crane  foundations.  Heavy  bosses  next  light  arms  are 
ever  a  source  of  danger,  and  there  comes  a  limit  to 
bracketing  and  the  use  of  curved  and  filleted  connections, 
beyond  which  fracture  is  likely  to  result,  either  during 
cooling,  or  tooling,  or  in  service.  It  is  certain  that  there 
are  large  numbers  of  castings  in  use  which  are  always 
perilously  near  fracture,  and  which  only  await  the  appli- 
cation of  some  sudden  and  unusual  stress  to  do  so.  The 
effects  of  and  the  amount  of  such  tensile  forces  are 
often  very  apparent  in  the  bosses  of  toothed  wheels,  fly- 
wheels, heavy  pulleys,  and  beds,  which  have  to  be 
divided  or  split  with  plates,  to  be  either  bolted  or  bonded 
together  subsequently.  The  divided  bosses  are  often 
drawn  apart  in  cooling,  leaving  the  divided  portions 
^  in.,  or  even  more,  wider  than  they  were  at  the  time  of 
casting,  an  ocular  demonstration  of  the  stresses  which 
occur  in  cooling.  This  splitting  is  adopted  as  a  neces- 
sary precaution  against  fracture,  though  it  increases  the 


120  PRACTICAL  IRON  FOUNDING 

expense  and  entails  bonding  or  bolting,  and  is  often 
unsightly.  But  it  is  better  than  a  fractured  casting. 

Although  mass  in  certain  parts  menaces  the  strength 
of  some  castings  of  the  class  which  we  have  been  con- 
sidering, there  are  many  examples  in  which  mass  is 
necessary  for  strength.  It  occurs  in  those  cases  in  which 
large  sections  being  unavoidably  adjacent,  parts  must  be 
suitably  proportioned.  A  familiar  example  of  this  kind 
occurs  in  spur-wheel  castings.  When  the  arms  of 
these  are  made  of  J_ -section,  as  when  moulded  from  full 
patterns,  these  are  more  liable  to  fracture  than  when 
the  arms  are  of  I  -section,  and  the  rim  of  the  Q-  section. 
In  the  latter  case  the  sections  are  all  about  equally 
proportioned,  and  such  wheels  seldom  break  under  severe 
stresses. 

In  the  second  place,  if  the  shrinkage  of  a  casting  is 
artificially  hindered  to  any  important  extent  it  is  liable 
to  fracture.  This  is  especially  likely  to  happen  in  large 
loam  moulds,  and  is  the  reason  why  courses  of  loam 
bricks  are  inserted,  and  why  the  hard  bricks  must 
frequently  be  partially  or  entirely  dislodged  before  the 
casting  has  arrived  at  the  black-heat  stage.  Loam  bricks 
in  large  cylinder  cores  are  built  in  one,  two,  or  three 
vertical  courses.  They  are  also  laid  behind  top  and 
bottom  flanges.  In  both  cases  they  yield  to  and  are 
crushed  by  the  shrinkage  of  the  metal,  that  in  the  cir- 
cumferential direction  in  the  first  instance,  and  the 
shrinkage  in  the  vertical  in  the  second.  But  for  this 
precaution  such  castings  would  fracture  by  their  own 
shrinkage  occurring  against  unyielding  bricks,  more 
than  one  instance  of  which  the  writer  remembers.  And 
it  is  often  necessary  to  remove  even  the  loam  bricks 
before  the  shrinkage  has  proceeded  far.  Sometimes 


SHRINKAGE— CURVING— FRACTURES,  ETC.     121 

nearly  all  the  bricks  are  loosened  and  thrown  down  into 
the  middle  of  the  core  while  the  casting  is  still  shrinking 
— a  hot  job  for  the  labourers,  but  a  safeguard  against 
the  chance  of  fracture. 

Some  plated  castings  are  exceedingly  liable  to  fracture. 
If  a  large  plate  is  free  to  shrink  it  is  quite  safe :  but  if  it 
is  tied  with  several  strong  webs  or  ribs  it  is  not  so.  I 
remember  some  bed  castings  which  were  plated  all  over 
at  top  and  bottom,  with  only  small  holes  to  get  the 
cores  out  of,  and  several  of  these  broke  in  succession. 
The  trouble  was  got  over  by  substituting  ribs  for  the 
plates,  which  again  were  too  massive,  and  tied  too  much, 
and  being  unable  to  yield  much  in  any  direction  they 
fractured  about  the  central  boss.  The  better  plan,  how- 
ever, is  not  to  plate  beds  at  top  and  bottom,  but,  even 
though  the  top  is  left  solid,  to  cast  ribs  only  on  the 
bottom.  And  it  is  usually  better  not  to  insert  dried  sand- 
cores  in  such  beds,  but  green-sand  ones  only,  or,  when 
practicable,  to  let  the  bed  deliver  its  own  green-sand 
cores.  I  remember  some  large  circular  bottom  tank- 
plates  for  water-cranes  which  sometimes  split  in  a  radial 
direction.  This  was  prevented  by  splitting  them  in  the 
mould  with  plates  and  filling  up  the  places  with  rust 
cement  afterwards.  The  reason  is  clear.  The  major  cir- 
cumference was  so  great  that  the  shrinkage  going  on 
round  there  put  the  metal  in  excessive  tension,  and  as  it 
could  not  move  towards  the  centre  on  the  solid  metal 
there,  it  parted.  Here,  too,  the  shrinkage  was  partly 
delayed  by  the  presence  of  ribs  and  a  deep  facing  round 
the  edge. 

Faults  and  Wasters. — An  engineer's  specification  for 
the  quality  of  cast  iron  runs  substantially  as  follows: 

"The  castings  shall  be  clean  and  sound,  both  extern- 


122  PRACTICAL  IRON  FOUNDING 

ally  and  internally,  and  shall  be  carefully  fettled  and 
smoothed.  They  shall  be  free  from  honeycombing,  blow- 
holes, scabs,  cold  shuts,  draws,  and  other  defects.  No 
stopping  up  or  plugging  is  on  any  account  to  be  per- 
mitted. No  castings  shall  be  made  in  open  sand.  Cores 
must  be  cast  in  accurately.  No  more  than  five  per  cent, 
variation  in  weight  will  be  allowed  on  either  side.  The 
metal  shall  be  remelted  once  in  the  cupola,  and  free  from 
any  admixture  of  cinder  iron,  or  other  inferior  material. 
It  shall  be  uniformly  tough  and  close-grained.  It  shall 
be  of  such  strength  that  a  turned  bar  having  an  area  of 
two  square  inches  shall  bear  a  tensile  strain  of  not  less 
than  from  16,000  Ib.  to  18,000  Ib.  per  square  inch  without 
breaking.  A  test-bar  3  ft.  between  supports,  by  2  in.  deep 
by  1  in.  thick  shall  bear  a  cross  breaking  strain  of  not 
less  than  from  28  cwt.  to  30  cwt.,  with  a  deflection  of  not 
less  than  J  in.  or  J  in.  before  breaking." 

Honeycombing. — Fig.  54  is  drawn  to  illustrate  the  ap- 
pearance of  a  spongy  top  face  of  a  column  casting.  The 
sponginess  may  be  greater  or  less  in  extent  than  that  in- 
dicated by  the  drawing;  but  the  general  appearance  is 
unmistakable,  and  the  term  spongy  or  honeycombed  ex- 
presses exactly  that  appearance.  The  holes  will  range 
from  the  size  of  a  pin's  head  to  that  of  a  pea  or  a  hazel- 
nut.  When  larger,  they  have  gone  past  mere  spongi- 
ness, and  are  termed  blow-holes.  Often,  as  in  blow- 
holes, the  worst  does  not  appear  on  the  surface— a  film 
of  metal  conceals  a  lot  of  honeycombing.  A  foreman  or 
an  inspector  will  try  the  most  minute  holes  with  a  bit  of 
wire  or  a  long  pin,  and  often  discover  in  that  way  that 
a  very  small  hole  on  the  surface  will  extend  for  several 
inches  beneath  the  surface,  opening  out  really  into  a  large 
blow-hole.  Such  sponginess  is  almost  invariably  found, 


SHRINKAGE-CURVING- FRACTURES,  ETC.     123 


when  present,  on  the  upper  surface  of  castings,  where 
the  pressure  is  least;  seldom  on  the  lower,  where  it  is 
greatest.  In  some  positions  it  is  of  relatively  little 
moment;  in  others  it  should  condemn  the  casting. 
Those  parts  which  are  subject  wholly  to  tension,  as  the 
bottom  flanges  of  girders,  should  never  be  passed  if  the 
honeycombing  is  at  all  extensive  or  deep.  In  the  case  of 
lugs  subject  to  tension,  honeycombing,  such  as  that 


FS-s 


$$?; 


FIG.  54.  FIG.  55. 

HONEYCOMBING. 

shown  in  Fig.  55,  is  quite  condemnatory,  even  though 
all  the  rest  of  the  casting  is  perfectly  sound.  Honey- 
combing on  column  flanges  is  also  serious,  because  the 
stability  of  a  column  largely  depends  on  flanges,  and 
the  strain  of  the  bolts  is  liable  to  pull  such  flanges  off. 
Sponginess  down  one  side  of  a  column  may  or  may  not 
be  serious,  dependent  on  its  extent  and  depth.  A  prac- 
tised observer  can  usually  form  a  correct  opinion  about 
that  by  probing,  and  by  general  appearance;  but  when 


124 


PRACTICAL  IRON  FOUNDING 


columns  have  to  be  subjected  to  severe  stress,  it  is  better 
to  condemn  all  which  show  any  traces  of  sponginess. 
They  can  be  cast  well  if  the  mould  is  properly  vented, 
the  metal  clean,  and  sufficient  risers  put  on.  Minute 
cracks  in  columns  have  sometimes  been  pened  over  with 
a  hammer.  The  same  practice  is  resorted  to  when  there 
are  honeycombed  surfaces,  the  hammer-blows  closing 
them,  and  smoothing  the  surface 
over.  The  most  satisfactory  test  for 
the  closeness  of  grain  and  freedom 
from  sponginess  of  a  column  is  the 
hydraulic,  just  as  it  is  used  in  the 
case  of  water-  and  steam-pipes. 

Blow-holes. — The  utmost  care  does 
not  always  suffice  to  prevent  these. 
They  are  due  to  insufficient  venting 
of  the  mould  or  core,  to  moisture,  and 
to  the  entanglement  of  air  in  the 
molten  metal.  Ample  venting  and 
steady  pouring,  with  the  use  of  risers, 
are  the  best  preventives  of  blow- 
holes. Unfortunately,  they  are  very 
often  concealed  by  a  film  of  metal,  as 
in  Fig.  56.  Hence  the  top  faces  of 
all  castings — which  can  always  be 
known  by  the  marks  left  from  cut-off  runners,  risers,  and 
chaplets — should  be  tested  with  hammer-blows,  when 
hollow  sounds  will  indicate  the  existence  of  concealed 
blow-holes,  and  a  sharp  blow  will  break  through  the  thin 
film.  Another  way  to  detect  them  is  to  thrust  a  fine  wire 
in  some  of  the  suspicious-looking  small  holes  when  such 
are  present,  when  it  will  often  penetrate  several  inches, 
revealing  the  fact  that  there  is  a  blow-hole  beneath.  A 


FIG.  56.— A  BLOW- 


HOLE. 


SHRINKAGE—CURVING—FRACTURES,  ETC.     125 

smooth  skin  will  often  conceal  hidden  faults  of  this  kind. 
Fig.  56  illustrates  an  extensive  blow-hole  in  section  below, 
and  its  locality  and  extent  are  indicated  by  dotted  lines  in 
plan  above.  Such  blow-holes  seldom  occur,  except  on  the 
upper  portions  of  castings.  These  often  extend  over  large 
areas  without  any  external  indication  of  their  presence, 
because  a  thin  film  of  metal  so  frequently  covers  and  en- 
closes them.  They  exist  either  with,  or  without  associa- 
tion with  general  sponginess.  As  they  generally  occur  on 
the  top,  and  as  they  are  often  completely  hidden,  it  is  ne- 
cessary to  test  all  castings  along  their  top  faces  with  smart 
blows  from  a  hand-hammer.  Such  blows  do  no  harm  to  a 
good  casting;  but  they  will  either  return  a  hollow  sound  or 
break  through  the  skin,  if  large  blow-holes  are  underneath. 
Blow-holes  in  castings  are  less  serious  when  they  occur 
in  those  portions  subject  to  compression  than  in  those 
subject  to  tension.  A  few  blow-holes  occurring  at  inter- 
vals in  the  former  would  not  sensibly  increase  the  risk  of 
crushing;  but  in  the  latter  they  would  be  highly  danger- 
ous. Blow-holes  in  the  neutral  axis  of  a  casting  are  of  no 
moment.  This  is  illustrated  by  the  fact  that  holes  may 
be  drilled  in  the  neutral  axis  of  a  test-bar,  and  the  drilled 
bar  will  sustain  the  same  load  as  a  solid  bar :  on  the 
other  hand,  if  the  bar  were  turned  upside  down,  bring- 
ing the  thinner  metal  into  tension,  it  would  fracture 
quickly.  The  fact  is  also  illustrated  by  the  practice  of 
lightening  out  a  girder  along  the  neutral  plane.  Spongi- 
ness on  the  compression  side  of  a  casting  will  slightly  in- 
crease its  deflection;  but,  all  the  same,  it  is  risky  to  pass 
work  in  which  blow-holes  occur,  even  in  localities  subject 
to  little  or  no  tensile  stress;  because  if  a  casting  is  blown 
in  one  place,  it  may  also  be  so  in  another,  of  which  no 
indications  are  visible. 


126  PRACTICAL  IRON  FOUNDING 

Scabs. — An  extensive  scab  is  shown  in  Fig.  57  at  A. 
These  occur  on  all  parts  of  castings — top,  bottom,  and 
sides.  They  are  due  to  the  washing  away  of  sand  caused 
by  hard  ramming,  to  weak  sand,  and  bad  venting.  The 
fettlers  may  chip  them  off;  but  an  inspector  can  see 
where  such  extensive  chipping  has  been  done,  and  all 
castings  that  show  signs  of  much  scabbing  should  be 
condemned.  It  is  not  because  the  scab  has  been  cut  off, 
but  because  its  presence  is  a  sure  indication  that  there  are 
masses  of  sand,  corresponding  in  size  with  the  scab,  im- 


At 

FIG.  57. — SCABBING. 

bedded  somewhere  in  the  body  of  the  casting.  Such 
masses  may  or  may  not  come  to  the  surface.  If  invisible, 
they  constitute  a  hidden  source  of  danger.  It  is  quite 
likely  that  the  corresponding  hole  or  holes  are  not  to  be 
found,  being  perhaps  covered  with  films  of  metal,  but 
there  is  no  doubt  about  their  existence  somewhere.  So 
that  the  presence  of  extensive  scabbing  is  quite  sufficient 
to  condemn  the  castings  in  which  it  occurs  as  unsound. 

The  causes  of  scabs  are  various.  As  just  stated,  hard 
ramming  is  liable  to  cause  them.  So  also  is  using  sand  of 
too  close  texture,  or  working  it  too  wet,  When  ramming 
a  mould,  regard  must  be  had  to  the  nature  of  the  casting, 


SHRINKAGE— CURVING— FRACTURES,  ETC.     127 

and  the  particular  section  of  the  mould  which  is  being 
rammed.  Metal  will  not  lie  kindly  on  a  hard  bed,  but 
will  bubble,  the  air  not  getting  away  with  sufficient 
rapidity,  and  bubbling  will  result  in  the  detachment  of 
flakes  of  sand,  and  consequent  scabbing.  If,  on  the  con- 
trary, the  sand  is  rammed  too  softly,  the  pressure  of  the 
metal  will  produce  lumpy  castings.  The  moulder  has 
therefore  to  ram  the  sand  sufficiently  hard  to  resist  the 
pressure  of  metal,  yet  so  soft  that  bubbling  shall  not 
take  place.  The  practical  result  is  a  kind  of  compromise. 
The  lower  stratum  of  sand  is  rammed  hard,  and  freely 
vented,  and  an  upper  stratum  of  an  inch  or  two  in  thick- 
ness is  rammed  more  softly.  The  metal,  therefore,  lies 
upon  a  comparatively  soft  cushion,  which  is  supported 
by  a  firm,  well-vented  backing.  The  lower  portions  of 
moulds  are  not  as  a  rule  rammed  so  hard  as  the  sides 
and  top,  since  the  gas  can  escape  more  readily  from  the 
latter  than  from  the  former.  A  hard-rammed  mould  will 
be  productive  of  less  risk  in  the  case  of  a  heavy  than  in 
that  of  a  light  casting.  Another  cause  of  scabbing  is  the 
leaving  of  risers  and  feeder  heads  open  during  the  actual 
pouring  of  metal. 

Choking  of  vents  will  produce  scabbing,  hence  the 
reason  why  the  vent  openings  are  always  closed  against 
the  face  of  a  mould.  Excessive  moisture  in  a  mould  will 
produce  scabbing  by  the  generation  of  steam  in  quantity. 
The  moisture  may  be  due  to  overmuch  watering  of  the 
sand  in  the  first  place,  or  to  the  abuse  of  the  swab  at  the 
time  of  mending  up  in  the  second.  The  amount  of  mois- 
ture in  a  mould  should  be  just  so  much  as  is  necessary 
to  effect  the  consolidation  of  the  sand — anything  in 
excess  of  that  is  injurious.  Too  much  sleeking  with  the 
trowel  also  is  injurious,  and  too  thick  an  application  of 


128 


PRACTICAL  IRON  FOUNDING 


blackening,  whether  wet  or  dry,  followed  by  hard  sleek- 
ing, is  a  fruitful  cause  of  scabbing,  the  blackening  and 
the  sand  beneath  flaking  off  at  the  time  of  pouring. 

Cold  Shuts. — Fig.  53  illustrates  the  defect  which  is 
termed  a  cold  shut.    Its  presence  should  condemn  any 
casting,  no  matter  where  it  occurs.    The  casting  is  really 
as  good  as  fractured    where  the   cold  shut  occurs.    It 
means  this:  that  the  metal  has  been  poured  cold  and 
dead,  or  that  the  metal  has  had  so  far  to  travel  in  the 
mould  that  it  has  become  chilled;   consequently,  when 
opposing  currents  meet,  they  do 
not  mix  as    perfect  liquids,   but 
only  to  a  partial  extent.    Being 
so  cold,  they  form  a  joint  or  im- 
perfect union,  much  like  a  bad 
weld.    These  are  also  caused  by 
using  poor  iron  with  no  life  in  it, 
or  by  using  iron  badly  melted,  as 
well  as  by  allowing  iron  to  remain 
too  long  in  the  ladle  before  pour- 
ing.  When  only  a  moderate  stress 

comes  on  the  casting,  the  cold  shut  becomes  the  weak 
link  in  the  chain.  These  shuts  can  usually  be  recognized 
by  the  rounded  appearance  of  the  edges  along  the  irre- 
gular groove  or  fissure  where  the  metals  have  met. 

Draws. — These  must  not  be  confounded  with  blow- 
holes, or  with  general  honeycombing.  Draws  are,  of 
course,  sources  of  weakness;  but  they  differ  from  blow- 
holes and  sponginess,  in  cause  and  in  characteristics. 
They  are  not  due  to  the  presence  of  air  or  dirt,  and  they 
are  not,  as  a  rule,  visible  on  the  surface.  The  better — 
that  is,  the  stronger — the  metal  is,  the  more  liable  is  it 
to  draw.  And  the  draws  occur  in  the  heart  of  the  thick- 


FIG.  58.— A  COLD 
SHUT. 


SHRINKAGE— CURVING— FRACTURES,  ETC.     129 

est  parts  of  the  casting.    They  are  due  to  unequal  rates 
of  cooling,  and  to   crystallization;    the  outside   of  the 
casting  sets  firmly  while  the  interior  is  still  molten,  or, 
at  least,  viscous.    As  the  interior  shrinks,  the  outside 
will  not  yield,  and  so  the  interior  metal  shrinks  on  itself, 
becoming  drawn  towards  the  outside  metal.    Then  one  of 
two  things,  or  both,  must  happen:  the  crystallization 
will  be  large,  coarse,  "  open  grained,"  and  proportion- 
ately weak,  or  a  cavity  will  be  left  about  the  centre. 
Given  a  tough,  strong  iron,  and  great  disparity  in  thick- 
ness of  metal,  favourable  to  the  more  rapid  cooling  of 
some  sections  than  others,  and  the  metal  is  certain  to 
become  drawn.    Hence,  what  some  people  think  must  be 
a  good  strong  casting  is  a  weak  and  uncertain  one.  As  a 
blow-hole  and  a  draw  are  due  to  entirely  different  causes, 
so  their  appearances  are  quite  different  and  quite  unmis- 
takable.    A  blow-hole  is  bounded  by  smooth  concave 
faces  or  edges.  A  hole  caused  by  a  draw  always  has  sharp, 
jagged  boundaries,  generally  of  very  irregular  outline. 
As  there  are  great  differences  in  the  dimensions  of  blow- 
holes, so  there  are  in  the  dimensions  of  holes  caused  by 
drawing.    Blow-holes  merge  into  mere  sponginess;  draws 
diminish  down  to  mere  openness  or  extreme  coarseness 
of  crystallization.    Some  holes  due  to  drawing  are  so 
large  that  two  or  three  fingers  may  easily  be  inserted  in 
them ;  others  will  barely  admit  a  pin  between  the  coarse 
crystals.     Draws,  like  many  blow-holes,  are  generally 
concealed  until  the  casting  fractures;  but  their  presence 
is  often  indicated  by  a  slight  depression  of  the  surface 
adjacent,  or  by  the  presence  of  a  small  hole  leading  from 
the  surface  adjacent  into  them.    Blow-holes  generally 
occur  on  or  near  the  upper  surface  of  castings;  draws 
may  occur  anywhere,  in  the  bottom  as  well  as  in  the  top 

K 


130  PRACTICAL  IRON  FOUNDING 

of  the  mould;  in  fact,  they  are  often  more  likely  to  occur 
in  the  bottom.  Thus,  if  a  mould  is  of  no  very  great  depth, 
and  it  is  fed  during  the  period  while  the  casting  is  setting 
with  fresh  supplies  of  molten  metal  over  the  parts  where 
the  metal  is  thickest,  drawing  will  be  prevented.  But  if 
there  is  thick  metal  in  the  bottom,  the  chances  are  that 
drawing  will  take  place  there.  On  the  other  hand,  in  a 
deep  casting  not  fed,  heavy  metal  in  the  bottom  will  not 
be  likely  to  draw,  because  the  superincumbent  liquid 
mass  will  feed  it;  but  the  top  metal  will  be  likely  to 
draw. 

All  draws  are  preventible  by  some  method  or  another, 
either  by  alteration  of  design,  or  by  the  adoption  of  cer- 
tain precautions  on  the  part  of  the  moulder.  Engine 
cylinders  are  capital  object-lessons  in  the  drawing  of 
castings.  They  are  always  made  of  tough,  stiff  metal, 
and  invariably  in  localities  where  there  is  much  excess 
of  metal  some  may  be  confidently  looked  for.  So,  too, 
are  large  weights,  such  as  are  often  cast  for  test  loads 
and  for  foundry  use.  In  such  weights  there  is  always  a 
depression  on  the  top  face,  due  to  the  internal  shrinkage, 
and  if  such  weights  are  broken,  there  is  always  a  central 
cavity  also,  or  else  very  open  crystallization.  Again,  sup- 
posing a  girder  made  like  Fig.  59,  and  the  light  and 
heavy  flanges  are  tied  with  ends  or  with  cross  ribs,  the 
probability  is  that  in  the  vicinity  of  the  union  of  the  ribs 
with  the  thick  flange  there  will  be  a  draw,  as  at  a,  and 
depressions  at  b,  c,  c.  In  the  case  of  this  girder,  having 
a  very  heavy  bottom  flange,  and  pockets,  A,  for  trimmer 
girders  cast  on  one  side,  and  brackets,  J5,  on  the  other, 
there  is  every  chance  of  a  draw  occurring  in  the  thickest 
part.  Or,  if  an  actual  open  space  does  not  occur,  the 
crystallization  will  be  very  open,  as  shown  at  a.  The 


SHRINKAGE— CURVING— FRACTURES,  ETC.     131 

obvious  alternative  is  to  lessen  the  mass  of  the  bottom 
flange  and  to  put  smaller  radii  in  the  angles.  In  the 
case  of  the  column  head,  Fig.  60,  putting  a  straight  core 


1= 

A 

j 

/ 

>   I 

Fm.  59.— A  DRAW. 

through,  the  side  A  masses  too  much  metal  at  that 
locality,  and  there  will  be  a  draw  at  a,  with  probably  a 
very  slight  circular  depression  of  metal  on  the  outside  or 
inside,  and  the  column  will  not  be  any  stronger — prob- 


FIG.  60.  FIG.  61. 

DRAWS,  AND  HOW  TO  AVOID  THEM. 

ably  weaker — than  as  if  it  were  cored  out  to  an  equal 
thickness,  as  shown  at  B. 

Fig.  61,  side  A,  shows  the  effect  of  a  heavy  belt  and 
thick  bracket  in  combination,  in  producing  a  draw.  At 
side  By  with  the  belt  shown  and  bracket  made  no  thicker 


132 


PRACTICAL  IRON  FOUNDING 


than  the  thickness  of  the  metal  in  the  body  of  the 
column,  no  draw  will  occur. 

In  these  instances  there  would  not  he  any  appreciable 
risk  of  fracture,  because  the  top  flange  is  free  to  shrink 
inwards;  but  in  some  cases  the  risk  of  fracture  becomes 
serious.  It  is  serious  when  thick  and  thin  adjacent  parts 
are  so  tied  that  they  are  not  left  free  to  shrink.  Heavy 
mouldings  on  columns  ought,  therefore,  always  to  be 
cored  out,  to  leave  approximately  the  same  section  every- 
where. 

The  tendency  to  draw  is  lessened,  and  the  strength  of 


FIG.  62.  —  EFFECT  OF|A  RADIUS. 


castings  increased,  by  abolishing  all  keen  internal  angles. 
This  rule  is  of  universal  application.  The  evil  of  sharp 
angles  is  seen  chiefly  in  flanges  which  have  to  take  the 
pull  of  screw-bolts.  In  Fig.  62  the  flange  A  would  be 
almost  certain  to  fracture  when  under  moderate  stress 
only.  The  flange  B  would  possess  the  maximum  of 
strength.  In  the  flange  C  the  radius  would  be  rather 
overdone,  and  the  flange  too  thick.  The  two  extremes  — 
a  very  thick  flange  and  a  very  large  radius  —  would  prob- 
ably cause  the  draw  shown,  and  produce  fracture  under 
less  strain  than  that  which  would  be  required  to  frac- 
ture B.  There  is  no  advantage  in  a  very  large  radius. 
A  small  radius,  even  less  than  that  shown  at  B,  adds 


SHRINKAGE— CURVING— FRACTURES,  ETC.     133 

immensely  to  the  strength.  The  mere  strength  is  not 
that  chiefly  due  to  the  increase  of  metal,  but  in- 
directly to  the  regular  or  symmetrical  arrangement  of 
crystals  when  cooling,  which  occurs  when  there  are  no 
abrupt  re-entering  angles.  When  such  sharp  angles  do 
occur,  there  is  an  abrupt  break  in  the  arrangement  of 
the  crystals,  and  it  is  along  that  line  of  abrupt  break 
that  fracture  will  occur.  Hence  it  is  a  rule  that  no  iron 
castings  to  stand  stresses  should  ever  be  made  with 
keen  internal  angles.  They  should  be  filled  up  and  ob- 
literated with  radii,  hollows,  or  fillets,  as  they  are  vari- 
ously termed.  In  some  positions  the  omission  of  these 
is  not  of  much  importance;  but  in  others  their  omission 
will  certainly  ensure  fracture. 

It  is  rather  fortunate  that  the  moulder's  instinct 
prompts  him  to  insert  those  radii  in  moulds  when  they 
are  not  put  on  the  pattern;  but  as  he  will  not  incur  too 
much  responsibility,  he  generally  breaks  the  edge  with  a 
hollow  sleeker,  which  is  much  better  than  nothing  at  all. 
And  many  a  flanged  casting  would  be  broken  in  the  mould 
before  ever  it  saw  the  light  of  day  but  for  the  precaution 
the  moulder  takes  of  digging  away  sand  from  between 
adjacent  flanges  or  ribs,  and  from  between  flanges  and 
box-bars,  and  so  permits  free  shrinkage  to  take  place. 
Without  this  precaution,  the  hard  sand  in  the  mould 
would  prevent  the  full  shrinkage  from  occurring,  and  the 
tension  put  on  the  casting  by  shrinkage  stresses  would 
be  greater  than  the  tenacity  of  the  red-hot  or  black-hot 
casting. 

Lapping  joints. — A  column  which  has  been  chipped 
heavily  along  the  flask  joints  should  be  carefully  exam- 
ined, because  that  is  due  to  the  shifting  of  the  flasks  on 
one  another,  or  to  the  bad  mending  of  a  broken  mould. 


134 


PRACTICAL  IRON  FOUNDING 


It  means  that  the  metal  will  be  thinned  along  the  joints 
by  the  amount  of  overlap  which  has  been  chipped  off. 
Lapping-joints  like  those  shown  in  Fig.  63  are  unsightly, 
besides  detracting  from  the  strength  of  the  casting.  The 
strength  being  measured  by  the  diminished  section  at  a, 
instead  of  at  b,  lap  to  the  extent  shown  in  the  figure  ought 
to  condemn  a  casting,  even  though  a  sound  one.  In 
Fig.  63,  A  is  a  section  through  a  true  column,  and  B  a 
section  through  one  which  has  overlapped.  Some  very 
slight  amount  of  overlap  is  almost  unavoidable  in  job- 
bing work,  for  which  special  flasks  and  patterns  are  not 
made.  But  it  should  never  exceed,  say,  y\  in.,  or  tV  in., 


FIG.  63. — LAPPING  JOINTS. 

at  a.  When  it  becomes  -J-  in.  or  -£%•  in.,  it  is  too  much 
to  be  passed.  If,  in  addition  to  the  overlapping,  the  core 
happens  to  be  out  of  centre  sideways,  then  the  thickness 
of  metal  will  be  still  further  diminished.  Sometimes 
flanges  overlap,  as  shown  at  C.  Then,  if  they  are  faced, 
their  thickness  is  reduced  by  the  amount  of  overlap. 
If  they  have  to  bed  on  stone  without  facing  them,  the}7 
look  unsightly. 

Pressure  in  top  and  bottom. — Owing  to  the  marked  dif- 
ference in  the  strength  of  cast  iron  in  tension  and  com- 
pression, it  is  usual,  when  practicable,  to  cast  those 
portions  of  work  which  are  to  be  in  tension  in  the  bottom 
of  the  mould.  All  the  advantage  to  be  derived  from  closer 


SHRINKAGE— CURVING— FRACTURES,  ETC.     135 

metal  is  thus  secured.  This  is  practicable  in  the  case  of 
girders  subject  to  uniform  stress  in  one  direction  only. 
But  it  is  not  applicable  to  columns  on  which  the 
stresses  are  either  uniform,  or,  if  variable,  acting  in  all 
directions  indifferently  at  different  times.  Thus,  for  in- 
stance, in  columns  sustaining  the  girders  of  a  bridge  sub- 
ject to  side  wind  pressure,  the  opposite  sides  of  the  col- 
umns will  in  turn  be  in  compression  and  tension.  This 
will  be  due  to  the  varying  directions  of  the  wind  against 
the  girders,  producing  bending  of  the  columns  to  one  side 
or  the  other.  Such  columns  should  in  theory  be  cast  up- 
right, with  heads.  But  it  is  seldom  done,  because  more 
costly  than  the  usual  method  of  casting  horizontally. 
Horizontal  casting  is  prolific  of  several  evils,  unless  very 
great  care  is  exercised  in  moulding,  coring  up,  and  pour- 
ing, and  in  subsequent  testing  and  inspection.  A  test- 
bar  will  give  the  strength  of  the  iron  in  the  column,  but 
it  tells  nothing  at  all  about  the  evils  above  alluded  to. 

The  reason  why  more  porous  metal  occurs  at  the  upper 
part  of  a  casting  than  at  the  bottom,  is  because  it  is  sub- 
ject to  little  pressure,  while  that  in  the  bottom  is  sub- 
jected to  a  considerable  liquid  pressure,  which  effects  its 
consolidation,  making  it  closer  and  stronger.  The  deeper 
the  mould  the  greater  the  pressure,  and  the  sounder 
will  be  the  lower  parts  of  the  casting.  This  is  the 
chief  reason  why  the  supplementary  metal  termed 
"head"  is  cast  upon  much  work  that  has  to  be  tooled, 
such  as  engine  cylinders,  hydraulic  cylinders  and  rams. 
All  the  spongy  metal  is  in  the  head,  and  when  this  is 
turned  or  sawn  off,  the  casting  below  is  uniformly  sound 
at  top  as  well  as  at  bottom.  This  sponginess  is  always 
present  in  some  degree  on  the  top  parts  of  all  castings,  and 
that  is  why  founders  always  try  to  cast  parts  which  have 


136  PRACTICAL  IRON  FOUNDING 

to  be  planed  or  otherwise  machined  bright,  in  the  bottom. 
If  the  top  part  of  a  casting  is  machined,  it  almost  always 
turns  out  spongy  unless  special  precautions  are  taken, 
such  as  running,  through  a  skimming  chamber,  or  al- 
lowing an  extra  thickness  to  be  machined  off,  or  cast- 
ing several  risers  or  flow-off  gates.  The  first-named 
consists  of  a  circular  chamber  set  right  in  the  way  of 
the  course  of  the  metal,  and  which  is  so  arranged  as  to 
impart  a  swirling  motion  to  the  metal,  sending  the  lighter 
matters  upwards  into  a  riser  above,  and  leaving  only  clean 
metal  to  pass  on  into  the  mould  (see  p.  155).  The  third 
named  means  that  there  is  a  slight  flow- through  of  metal 
in  the  mould  permitted,  the  lighter  matters  passing  out 
into  vertical  channels  or  risers  (see  p.  160).  But  these  de- 
vices do  not  wholly  prevent  sponginess.  They  do,  however, 
effect  removal  of  the  scurf,  and  that  is  something,  since 
the  presence  of  this  is  a  fruitful  source  of  sponginess. 
But  the  greater  natural  porosity  of  the  metal  on  the  top  of 
a  casting  cannot  be  wholly  removed. 


CHAPTEK  VIII 

PRINCIPLES  OF  GREEN  SAND  MOULDING 

THIS  branch  embraces  much  the  largest  proportion  of 
cast  work  done,  being  not  only  cheap,  but  sufficiently 
good  for  all  except  some  few  special  purposes.  The  mean- 
ing of  the  term  green  sand  was  explained  on  p.  6.  The 
methods  of  moulding  in  green  sand  are  broadly  classified 
under  three  great  divisions,  namely,  moulding  in  open 
sand,  by  bedding  in,  and  by  turning  over.  By  one  or  another 
of  these,  all  work  which  is  made  in  green  sand  is  accom- 
plished. 

Moulding  in  open  sand  signifies  that  the  mould  is  un- 
covered on  its  upper  face.  In  the  closed  moulds,  the 
metal  when  poured  is  arrested  at  a  certain  definite  stage 
by  the  face  of  the  sand  in  the  top  or  cope.  This  face  may 
have  any  contour,  irregular  or  otherwise,  but  the  upper 
face  of  a  casting  made  in  open  sand  can  only  be  truly 
horizontal,  which  fact  at  once  limits  the  utility  of  open 
moulds.  But  in  addition  to  this,  the  upper  surface  of  a 
casting  made  thus  is  always  irregular,  rough,  porous, 
unsound :  irregular  and  rough,  because  the  hot  bubbling 
iron  is  not  confined  against  a  face  of  sand,  but  begins 
to  set  before  the  commotion  due  to  the  evolution  of  its 
heat,  and  of  the  gases  and  air,  has  subsided — porous 
and  unsound,  chiefly  for  this  reason,  and  partly  be- 
cause it  is  not  cast  under  pressure,  as  are  all  closed 
moulds;  the  pressure  in  these  being  due  to  the  height  of 

137 


138  PRACTICAL  IRON  FOUNDING 

the  pouring-basin  above  the  surface  of  the  mould.  Cast- 
ings made  in  open  sand  are  therefore  only  employed  for 
very  rough  work,  never  for  ordinary  engineering  con- 
structions. Moulding  flasks,  back  plates,  foundation 
plates,  core  plates,  rough  weights  used  only  for  loading, 
and  similar  articles  are  made  in  open  sand. 

The  main  essential  in  this  class  of  work  is  to  have  the 
mould  perfectly  level,  a  matter  comparatively  unim- 
portant in  closed  moulds.  Hence,  either  a  level  bed  of 
sand  is  first  prepared,  and  the  pattern  or  skeleton  of  the 
pattern,  or  sectional  portion  of  the  pattern,  as  the  case 
may  be,  is  laid  upon  this  and  rammed,  or  the  pattern  is 
bedded  in  and  levelled  during  the  process  of  ramming. 
Venting  is  seldom  done  except  when  the  sand  happens 
to  be  of  very  close  texture,  but  the  air  comes  away  partly 
from  the  upper  face  of  the  casting,  partly  through  the 
bottom  sand. 

Usually  an  open  sand  mould  is  made  f  in.  or  ^  in. 
deeper  than  the  casting  is  required  to  be,  and  overflow 
channels  are  cut  around  the  edges  to  carry  off  the  super- 
fluous metal,  and  to  indicate  the  proper  time  for  the 
cessation  of  pouring.  A  good  deal  of  work  in  open  sand 
is  shaped  by  the  moulder  himself  with  the  aid  of  a  few 
strips  and  sweeps  only,  but  then  it  is  the  roughest  class 
of  moulded  work  done. 

Bedding  in. — This  signifies  the  moulding  of  patterns 
in  the  sand  of  the  foundry  floor,  the  position  of  the 
mould  being  in  no  respect  changed  from  the  commence- 
ment of  operations  until  the  time  of  casting.  In  this 
method  it  is  obvious  that  the  lower  faces  of  the  mould — 
those  which  are  formed  underneath  the  pattern — will 
not  be  easily  rammed,  and  may  be  harder  and  softer 
in  places. 


PRINCIPLES  OF  GEEEN  SAND  MOULDING    139 

When  work  is  bedded  in,  the  sand  is  dug  up  and 
loosened  to  a  sufficient  depth,  and  into  this  the  pattern 
is  beaten  with  heavy  wooden  mallets,  its  top  face,  when 
practicable,  being  tested  by  the  spirit  level — usually  in 
conjunction  with  winding  strips.  As  soon  as  a  very 
rough  impression  of  the  mould  is  thus  obtained,  an  inch 
or  two  of  facing-sand  is  strewn  or  riddled  over  the  whole 
area,  and  the  pattern  is  beaten  down  again.  This  ham- 
mering down  of  the  pattern  causes  the  sand  to  become 
harder  in  certain  sections  than  in  others — becoming 
hard,  it  also  offers  a  certain  resistance  to  the  further 
bedding  down  of  the  pattern.  This  consolidated  sand  is 
therefore  hatched  up  and  loosened,  and  if  need  be,  por- 
tions are  removed  with  the  trowel,  or  with  the  hands, 
until  the  pattern  has  been  made  to  bed  pretty  nearly 
alike  all  over.  Recesses,  pockets,  ribs,  flanges,  and  such 
like,  when  present,  have  to  be  filled  in,  by  tucking  the 
sand  underneath  and  around  them  with  the  hands,  the 
smaller  rammer  following  afterwards  where  possible. 
When  the  sand  is  thus  rammed  and  brought  up  level 
with  the  top  edge  of  the  pattern,  it  is  scraped  and  sleeked 
off,  and  the  joint  face  made  ready  for  the  cope.  The  face 
is  then  strewn  with  parting  sand,  and  the  cope  put  on, 
set  with  stakes,  and  rammed. 

Though  these  operations  are  in  general  outlines  very 
simple,  yet  in  their  practical  details  they  call  for  the 
exercise  of  as  much  skill  on  the  part  of  the  moulder  as 
those  involved  in  turning  over.  The  difficulty  in  bedding 
in  lies  chiefly  in  the  proper  consolidation  of  the  sand. 
If  the  sand  is  of  unequal  consistence,  scabs  and  blow- 
holes in  the  harder  portions  will  result,  and  swellings  on 
the  castings  over  the  softer  portions. 

Turning  over. — This   signifies   that   the    face   of  the 


140  PRACTICAL  IRON  FOUNDING 

mould  which  is  lowermost  at  the  time  of  casting,  is 
uppermost  at  the  commencement  of  ramming,  being 
subsequently  turned  over.  By  this  method  it  is  clear 
that  the  portion  of  the  mould  which  is  finally  lowermost 
will  be  rammed  as  evenly  and  well  as  the  upper  portion, 
since  it  has  already  been  in  the  top  at  the  earlier  stage 
of  ramming:  and  it  is  evident  that  the  consolidation  of 
the  sand  over  any  given  area  will  be  more  perfect  when 
it  has  been  rammed  directly  against  a  pattern,  than 
when  the  pattern  has  been  simply  beaten  down  into  a  bed 
of  sand.  But  it  is  also  clear  that  since  in  turning  over, 
the  whole  of  the  mould  is  contained  in  flasks,  this 
method  requires  more  box  parts  or  flask  sections,  and 
increases  the  weight  which  has  to  be  lifted  by  men,  or 
with  cranes,  or  travellers;  and  is  therefore  more  expen- 
sive than  bedding  in.  The  larger  and  heavier  the  work, 
the  greater  the  reason  then  why  bedding  in  should  be 
adopted  in  preference  to  turning  over.  In  massive  work, 
therefore,  the  preference  is  usually  given  to  bedding  in, 
but  in  moulds  of  small  and  of  moderate  size,  and  gener- 
ally for  work  of  the  best  class,  turning  over  is  the 
method  usually  adopted. 

Figs.  64  to  67  illustrate  the  moulding  of  a  trolly  wheel 
by  turning  over.  The  pattern  is  first  laid  with  its  upper 
face  downwards  on  a  temporary  cushion  of  sand  in  the 
flask,  A,  Fig.  64,  which  is  presently  to  form  the  top  or 
cope.  A  joint  face  is  made,  which  may  or  may  not  be  in 
the  same  plane  as  the  joint  edge  of  the  flask,  being  de- 
pendent on  circumstances.  It  is  often  convenient  to  slope 
the  sand  joint  up  or  down  when  the  relative  depths  of 
pattern  and  flask  require  it.  The  joint  is  strewn  with 
parting  sand.  Upon  this  the  flask  Bt  which  is  presently 
to  form  the  drag,  is  laid,  Fig.  65,  and  rammed  per- 


PRINCIPLES  OF  GREEN  SAND  MOULDING    141 

manently.    The  two  flasks  then  cottared  together,  are 
turned  over,  and  the  bottom  or  drag  B  is  laid  in  its 


FIG.  68. 


FIG.  69. 


FIG.  70. 
EXAMPLES  OP  TURNING  OVER. 

permanent  position  upon  a  bed  of  levelled  sand.  The 
cope  is  lifted  off,  its  loose  cushion  of  sand  knocked  out, 
and  the  upper  joint  face  of  the  drag  smoothed  over,  and 


142  PRACTICAL  IRON  FOUNDING 

strewn  with  parting  sand.  Fig.  66  represents  the  mould 
at  this  stage.  The  cope  is  then  placed  on,  swabbed, 
liftered,  and  rammed  permanently  with  the  runner  pin 
in  place.  The  flasks  are  then  parted  at  the  joint,  the 
mould  mended  and  blackened,  cored,  closed,  and  cot- 
tared,  and  the  pouring  basin  C  made.  Fig.  67  represents 
the  mould  closed  ready  for  pouring. 

The  next  illustrations,  Figs.  68  to  70,  are  those  of  a 
three-parted  mould.  It  is  obvious  that  the  groove  of  the 
sheave  wheel  there  shown  must  effectually  prevent  de- 
livery if  moulded  in  the  same  manner  as  the  trolly  wheel 
— that  is,  with  a  cope  and  drag  only.  Two  parting  joints 
are  necessary  to  enable  the  pattern  to  deliver,  and  in 
addition  the  pattern  itself  has  to  be  divided  through  its 
middle  plane.  Fig.  68  shows  that  stage  of  the  mould 
which  corresponds  with  the  stage  in  the  moulding  of  the 
trolly  wheel  seen  in  Fig.  64.  The  sand  in  A,  Fig.  67, 
forms  a  temporary  bedding  only  for  the  half-pattern, 
over  which  the  drag  B  is  rammed  for  permanence.  The 
flasks  A  and  B,  then  cottared  together,  are  turned  over, 
A  is  removed,  and  the  sand  knocked  out,  the  exposed 
joint  face  of  B  is  sleeked,  and  strewn  with  parting  sand, 
the  middle  part  rodded  and  liftered,  swabbed  with  clay- 
water,  and  rammed  approximately  level  with  the  pat- 
tern joint,  Fig.  69.  To  sustain  the  weak  narrow  zone 
of  sand  which  forms  the  pulley-groove,  nails  dipped 
in  clay-water  are  rammed  in — nailing — with  the  sand,  as 
seen  in  Fig.  70.  The  upper  half-pattern  is  then  put  on 
the  lower  half  and  weighted,  the  sand  rammed  to  the 
middle  plane  D  of  its  flange,  Fig.  69,  the  joint  sleeked 
over,  parting  sand  strewn  thereon,  and  the  cope  E  put 
on,  liftered  and  rammed.  The  flasks  are  then  parted,  the 
pattern  withdrawn,  the  mould  cleaned,  blackened,  cored, 


PRINCIPLES  OF  GREEN  SAND  MOULDING     143 

and  closed,  the  pouring  basin  F  made,  and  all  is  ready 
for  casting,  as  in  Fig.  69. 

Figs.  71  and  72  show  in  vertical  section  and  in  plan 
respectively  the  mould  through  a  column  which  has  been 
made  by  turning  over.  Here  the  top  and  bottom  boxes 
are  alike.  The  sand  in  the  top  is  liftered,  the  mould 


FIG.  71. 


FIG.  72. 
A  COLUMN  MOULDED  BY  TURNING  OVER. 

being  long,  is  poured  from  both  ends  simultaneously,  and 
strain  is  relieved  by  risers  or  flow-off  gates  placed  about 
the  central  portions  of  the  mould.  Chaplets  will  be 
noticed  by  which  the  core  is  maintained  centrally  in  the 
middle  part  away  from  the  core  prints. 

These,  in  bare  outline,  are  the  general  processes  of 
bedding  in,  and  of  turning  over.  I  have  purposely,  in 
order  to  avoid  confusing  the  mind  of  the  student,  omitted 


144  PRACTICAL  IRON  FOUNDING 

to  explain    certain   important   items    essential   to  safe 
moulding,  which  we  must  now  consider. 

Venting. — Vents  are  variously  made,  according  to  cir- 
cumstances. When  a  pattern  is  being  rammed,  the  sand 
by  which  it  is  surrounded  is  pierced  with  innumerable 
small  vent-holes  of  about  %  in.  in  diameter,  more  or  less. 
These  do  not  properly  come  quite  close,  but  only  to 
within  i  in.  or  %  in.  of  the  pattern.  When  vent-holes 
come  out  on  the  actual  mould  surface,  there  is  always 
risk  of  the  metal  entering  the  vents  and  choking  them, 
and,  by  preventing  the  escape  of  air  and  gas,  causing  a 
waster  casting.  All  the  small  vents  are  brought  into 
larger  ones,  and  the  positions  of  the  larger  ones  will 
depend  on  the  nature  of  the  mould.  For  instance,  when 
a  pattern  is  bedded  in,  and  the  area  of  the  mould  is 
large,  all  the  lower  surface  vents  are  carried  directly 
downwards  into  a  large  porous  reservoir  of  cinders, 
clinkers,  or  coke — hence  termed  a  coke-bed  or  cinder-bed. 
In  this,  layers  of  hay  alternate  with  layers  of  cinders, 
and  the  whole  is  covered  with  a  final  stratum  of  hay. 
This  bed  is  laid  at  a  depth  of  10  in.  or  12  in.  beneath 
the  lower  face  of  the  mould,  and  has  a  total  thickness, 
including  cinders  and  hay,  of  10  in.  or  12  in.  Into  this 
the  vents  are  carried,  and  from  it  the  air  is  led  away,  and 
escapes  through  vent-pipes.  Fig.  88,  p.  167,  illustrates  a 
mould  having  a  cinder-bed  and  vent-pipes.  The  larger 
vent-holes  are  made  with  a  vent-wire  of  J  in.  or  f  in. 
diameter,  usually  at  an  early  stage  of  the  bedding  in  of 
the  pattern,  or  as  soon  as  the  general  contour  of  the 
mould  is  obtained,  and  before  the  pattern  is  put  back  for 
final  ramming  up.  But  after  the  pattern  is  withdrawn, 
the  vent  openings,  if  not  already  closed  by  the  bedding 
in,  are  filled  up  by  the  consolidation  of  the  surface  sand 


PRINCIPLES  OF  GREEN  SAND  MOULDING     145 

with  the  hands  of  the  moulder,  which  invariably  follows 
upon  the  withdrawal  of  a  pattern  that  has  been  bedded 
in.  By  exerting  gentle  pressure  with  the  fingers  over  the 
whole  of  the  surface  in  detail,  the  moulder  ascertains 
what  sections  are  not  sufficiently  firm,  and  adds  fresh 
sand  in  those  parts,  using  the  rammer  for  the  purpose. 
At  the  same  time  he  closes  vent-holes  which  may  yet 
remain  open.  On  first  thoughts  it  may  seem  strange  to 
make  vents  and  then  close  their  openings,  but  the  air 
and  gas  will  force  their  way  under  the  liquid  pressure 
existing  in  the  mould,  through  an  inch  or  thereabouts  of 
intervening  sand,  to  the  vents,  while  the  metal  itself 
will  be  unable  to  do  so. 

Diagonal  vents  are  brought  from  the  sides  of  a  mould 
into  shallow  channels  or  gutters  which  are  cut  in  the 
sand,  forming  the  joints  of  the  mould,  and  are  thus 
carried  away  at  the  box  joints.  The  vents  from  the 
upper  surface  of  a  mould  are  brought  off  directly  through 
the  whole  area  of  the  upper  surface  of  the  cope  sand. 
In  Figs.  67  and  69,  the  upper  surface  vents  are  brought 
out  over  the  tops  of  the  copes  A  and  E  respectively, 
covering  the  whole  area.  The  venting  is  therefore  direct. 
Vents  in  the  drag,  in  work  which  is  turned  over,  are 
first  made  directly  to  the  pattern  face  before  turning 
over,  and  are  then  brought  out  at  the  joint  which  the 
under  surface  of  the  drag  makes  with  the  levelled  bed  of 
sand  on  which  it  rests.  The  necessary  connection  with 
the  outside  of  the  flasks  is  made  by  passing  a  long 
vent  wire  from  the  outside  between  those  faces  in  all 
directions.  The  vents  therefore  in  Figs.  65  and  67  pass 
from  the  lower  faces  of  the  mould  perpendicularly  through 
the  drags  B  and  B,  and  then  out  at  right  angles  herewith, 
on  a  level  with  the  sand  floor  upon  which  the  drags  rest. 

L 


146  PRACTICAL  IRON  FOUNDING 

The  vents  from  the  peripheries  of  these  moulds  are 
brought  out  diagonally  into  gutters  cut  into  the  mould 
faces,  and  the  air  escapes  through  the  joints  of  the 
flasks. 

Sand  which  is  rammed  hard  will  require  more  venting 
than  loosely  rammed  sand.  Free  open  sand  will  require 
less  than  close  loamy  sand.  The  red  sands  are  so  free 
and  open  that  for  many  kinds  of  light  work  no  venting 
is  required  at  all,  their  natural  porosity  being  sufficient 
to  allow  of  the  escape  of  the  air.  In  heavy  work  the 
vents  may  be  kept  farther  from  the  surface  than  on  light 
work.  The  more  moisture  present  in  a  mould  the  greater 
the  quantity  of  venting  necessary. 

Retention  of  Sand. — Another  important  matter  in 
moulding  is  the  artificial  binding  together  and  retention 
of  large  quantities  of  sand  in  their  boxes.  It  is  clear  that 
the  mere  ramming  of  a  large  mass  of  sand  in  a  flask,  with 
no  other  support  than  that  afforded  by  the  sides,  and  the 
bars  or  stays,  would  not  prevent  the  tumbling  out  of  por- 
tions of  that  sand  by  concussion,  or  even  by  reason  of  its 
own  weight.  Numerous  devices  are  therefore  resorted  to 
in  order  to  bind  or  secure  it,  both  during  moulding  and 
at  the  time  of  casting.  These  methods  are  rodding,  lifter- 
ing,  and  sprigging,  signifying  that  rods,  lifters,  and  sprigs 
or  nails  are  used  in  different  moulds,  or  in  different  por- 
tions of  the  same  mould,  as  binding  agents. 

Rodding. — This  means  that  masses  of  sand  which  by 
reason  of  their  large  amount  of  overhang  cannot  be  sup- 
ported and  stayed  by  the  bars  of  the  flask,  are  sustained 
by  means  of  iron  rods.  Thus,  as  a  typical  example,  a 
mass  of  sand  overhanging  a  flange  will  be  supported  by 
rods,  the  opposite  ends  of  which  are  either  sustained  by 
the  main  body  of  sand  in  the  mould,  or  upon  a  drawback 


PRINCIPLES  OF  GREEN  SAND  MOULDING     147 

plate,  or  on  any  ordinary  cast  iron  ring  or  frame,  such 
as  those  which  are  often  used  for  lifting  the  middle  sand 
in  some  kinds  of  bedded-in  moulds.  Eods  are  used  also 
in  turned  over  moulds,  in  the  middle  flasks,  which  are 
destitute  of  bars.  The  general  mode  of  rodding  and 
liftering  middle  parts  is  shown  in  Fig.  87,  p.  165,  rods  of 
square  bar  iron  being  placed  across  the  flask  and  sup- 
ported by  the  ledge  (see  Fig.  31  B,  p.  96)  that  runs 
round  the  inside  face.  The  lifters  depend  from,  and  are 
supported  upon  these.  Similar  rods  are  seen  in  the 
middle  part  in  Fig.  69,  p.  141. 

Lifters. — These  are  bent  rods  made  both  in  wrought 
and  in  cast  iron,  the  size  of  cross  section  and  length 
varying  with  the  dimensions  of  the  work.  They  may 
range  from  \  in.  to  J  in.  in  diameter,  and  from  4  in.  to 
24  in.  in  length.  They  rest  upon  the  rods  as  in  Fig.  87, 
p.  165,  or  are  suspended  from  the  box  bars  as  in  Fig.  92, 
p.  170,  and  are  set  and  laid  in  all  possible  positions 
wherever  sand  requires  support.  In  some  few  cases  they 
are  not  themselves  supported,  but  simply  act  as  binders 
within  the  sand,  their  bent  ends  resisting  the  tendency 
to  dislodgement  of  the  sand  in  mass.  But  when  practic- 
able they  should  be  suspended  from,  or  rest  upon,  rigid 
supports.  Judgment  is  required  even  in  the  apparently 
simple  matter  of  the  putting  in  of  lifters,  since  if  im- 
properly supported,  a  tumble-out  of  the  sand  and  lifters 
en  masse  will  probably  occur. 

Sprigging  or  nailing. — Common  cut  nails  are  employed 
for  strengthening  weak  sections  of  sand  which  are  too 
small  to  be  sustained  by  lifters.  Or  the  sprigs  may  be 
considered  as  auxiliary  to  lifters,  strengthening  in  detail 
the  sand  the  principal  mass  of  which  is  carried  by  the 
lifters.  In  all  work  where  there  are  small  isolated  bodies 


148  PRACTICAL  IRON  FOUNDING 

of  sand,  narrow  weak  edges,  projections,  etc.,  long  nails 
are  inserted  in  quantity  to  bind  those  to  the  main  body. 
The  nails  are  not  only  inserted  at  the  time  of  moulding, 
but  also  after  the  pattern  has  been  withdrawn.  Should  the 
mould  crack  or  show  signs  of  giving  way,  nails  are  thrust 
in  to  strengthen  it,  and  to  prevent  risk  of  the  sand 
becoming  washed  away  by  the  rush  of  metal.  In  the 
economy  of  mending  up,  these  nails  are  indispensable. 
An  example  of  sprigging  occurs  in  Fig.  70,  p.  141. 

Mending  up. — This  is  necessary  in  most  cases  except- 
ing those  in  which  the  patterns  are  made  for  standard 
use,  regardless  of  expense,  and  those  in  which  patterns 
are  moulded  by  machine.  The  causes  of  moulds  breaking 
down  are  numerous,  as,  for  instance,  badly  made  pat- 
terns destitute  of  taper,  of  rough  construction,  having 
overlapping  joints  in  the  wood  of  which  they  are  com- 
posed; the  leaving  those  pieces  fast  which  ought  properly 
to  be  loose,  too  soft  or  too  hard  ramming,  imperfect 
rodding  or  nailing,  insufficient  or  excessive  rapping, 
uneven  or  jerky  lifting.  These  are  the  principal  causes 
of  the  fracturing  of  moulds. 

At  the  time  of  withdrawing,  or  delivery  of  a  pattern, 
the  joint  edges  of  the  sand  are  swabbed,  in  other  words, 
they  are  just  damped  or  moistened  with  the  swab  or 
water  brush  in  order  to  render  the  sand  around  the 
edges  of  the  pattern  as  coherent  as  possible.  Then  the 
pattern  is  rapped,  that  is,  a  pointed  iron  bar  is  inserted 
in  a  rapping  plate  let  into  the  pattern,  or  otherwise  into 
a  hole  bored  into  the  pattern  itself,  and  the  bar  is  struck 
on  all  sides  in  succession  with  a  hammer,  so  loosening 
the  pattern  from  actual  contact  with  the  sand  in  its 
immediate  proximity.  A  lifting  screw,  or  else  a  spike,  is 
then  inserted,  several  screws  or  spikes  being  used  in  work 


PRINCIPLES  OF  GREEN  SAND  MOULDING     149 

of  large  dimensions,  and  the  pattern  is  lifted  gently, 
moderate  rapping  with  wooden  mallets  on  its  surface  and 
edges  being  continued  the  while. 

After  the  pattern  has  been  removed,  the  mould  is 
carefully  overhauled  to  note  the  extent  of  the  damage, 
if  any,  which  it  has  sustained.  If  the  lift  has  been  very 
bad  and  the  work  is  very  intricate,  it  is  better  not  to 
attempt  mending  up  at  all,  but  to  ram  the  pattern  over 
again.  If  the  edges  chiefly  are  broken,  it  is  in  some 
cases  desirable,  as,  for  instance,  in  moulds  taken  from 
loam  patterns,  to  put  the  pattern  into  place  again,  and 
make  good  the  sand  around  the  edges,  pressing  it  down 
with  the  trowel  and  increasing  its  coherence  by  means 
of  sprigs  and  the  use  of  the  swab.  If  the  damage  is  of 
quite  a  local  character,  that  portion  of  the  pattern  cor- 
responding therewith  can  often  be  taken  off  and  put  back 
in  the  mould  as  a  guide  by  which  to  mend  up. 

In  sections  which  are  inherently  weak,  a  stronger  sand 
should  be  employed  than  that  which  is  used  for  the 
general  facing  of  the  mould;  core  sand  may  in  certain 
sections  be  used  with  advantage.  In  most  broken  parts 
it  will  be  necessary,  where  the  main  pattern  or  portions 
of  the  pattern  are  not  utilized  for  the  purpose,  to  use 
mending  up  pieces.  These  are  strips  of  wood  cut  to  the 
outlines,  curved  or  otherwise,  of  the  broken  sections,  and 
held  against  those  sections  while  the  broken  sand  is 
being  repaired  and  made  good. 

In  green  sand  moulding  there  is  a  process  termed  skin 
drying,  which  is  serviceable  as  a  means  of  slightly  stiff- 
ening an  otherwise  weak  section  or  area  of  sand.  It  con- 
sists in  partly  drying  the  surface  of  the  mould,  not  in 
the  stove,  but  with  devils  or  open  cages  containing  burn- 
ing coke  or  charcoal.  Or  a  red  hot  weight,  or  other  mass 


150  PRACTICAL  IRON  FOUNDING 

of  hot  iron,  is  suspended  in  close  proximity  to  the  mould 
for  the  same  purpose.  This  skin  drying  slightly  stiffens 
and  hardens  the  sand,  enabling  it  the  better  to  resist  the 
pressure  of  metal. 

The  mould  is  not  finished  at  this  stage.  Its  surface 
has  to  be  protected  with  blackening  or  blacking.  When  a 
mould  is  skin  dried  this  is  laid  on  before  the  drying  is 
done.  The  use  of  blackening  is  similar  to  that  of  the 
coal  dust  in  the  sand,  namely,  as  a  protection  against 
the  fierce  heat  of  the  metal.  But  the  coal  dust  being 
mixed  in  small  proportions  is  scattered  finely  among  the 
facing  sand,  while  the  blackening  continuously  covers 
the  face  of  the  mould.  The  blackening  being  made  either 
of  ground  oak  charcoal,  or  prepared  from  plumbago,  is 
essentially  carbon,  and  the  immediate  effect  of  contact 
of  the  molten  metal  therewith  is  the  formation  of  a 
gaseous  film  of  one  or  of  both  of  the  oxides  of  carbon. 
Thus  smoothness  of  surface  is  preserved,  because  the 
metal  is  prevented  from  coming  into  actual  contact  with, 
and  entering  into  the  interstices  of,  the  sand,  and  fusing 
its  surface,  with  the  production  of  a  hard  skin  of  silicate. 
The  action  is  further  assisted  by  the  coal  dust  in  the 
facing  sand.  Hence  the  reason  why  heavy  castings  re- 
quire a  thicker  coat  of  blackening,  and  a  thicker  stratum 
of  facing  sand,  than  lighter  ones. 

Wet  blacking  is  often  used  on  moulds  of  large  size,  and 
on  those  which  are  to  be  skin-dried.  This  is  blacking 
mixed  with  water,  thickened  with  clay,  and  laid  on  wet 
with  a  brush.  Blacking  in  its  ordinary  state  is  applied 
as  powder  and  sleeked  with  a  camel  hair  brush  and 
trowel. 

Pouring. — The  methods  of  pouring  or  running  a  mould 
are  varied.  Much  depends  on  this  apparently  simple 


PRINCIPLES  OF  GREEN  SA^7D  MOULDING     151 

matter.  .But  in  truth  there  is  nothing  in  moulders'  work 
which  is  insignificant  or  unimportant.  From  first  to  last 
care  in  little,  and  to  a  casual  observer,  trivial  things, 
has  to  be  scrupulously  exercised.  A  trifling  neglect  may, 
and  often  does,  ruin  the  work  of  several  hours,  or  of 
days. 

Since  the  conditions  of  liquid  pressure  exist  in  moulds, 
several  things  become  self-evident.  The  pouring  basin 
must  be  higher  than  the  highest  part  of  the  mould.  The 
liquid  pressure  on  any  given  portion  of  the  mould  will  be 
statically  equivalent  to  head  x  area  x  sp.  gr.  of  metal. 
The  pressure  on  a  mould  of  large  area  will  in  any  case  be 
very  great,  and  must  be  resisted  by  equal  and  opposite 
forces.  The  area  of  the  ingates  must  be  sufficient  to  fill 
the  mould  before  the  metal  has  time  to  become  chilled  or 
pasty.  Also  there  are  other  matters  of  a  purely  practi- 
cal character,  which  must  be  illustrated  to  be  properly 
explained. 

Various  methods  of  pouring  are  shown  in  Figs.  73  to  76, 
pp.  155-156.  A  mould  may  be  poured  direct  from  the  top, 
or  from  the  bottom,  or  from  both  top  and  bottom  simul- 
taneously, or  it  may  be  poured  from  one  side.  Most 
moulds  are  poured  from  the  top  direct,  Figs.  67,  69,  p.  141. 
When  they  are  of  considerable  depth,  or  when  it  is  de- 
sirable that  their  surface  or  skin  shall  be  clean  and 
smooth,  that  is,  not  roughened  or  cut  up  by  the  action 
of  the  metal,  they  are  run  from  the  bottom  or  from  the 
sides.  For  it  is  evident  that  metal  rising  quietly  in  a 
mould  will  not  cause  such  damage  to  surfaces  as  that 
which,  falling  from  a  considerable  height,  strikes  the 
sides  in  its  descent,  and  beats  heavily  on  the  bottom  of 
the  mould.  When  it  is  necessary  that  metal  shall  be 
poured  from  the  top  into  a  deep  mould,  its  cutting  action 


152  PRACTICAL  IRON  FOUNDING 

is  often  diminished  either  by  making  the  mould  in  dry 
sand,  or  by  placing  a  piece  of  loam  cake  at  the  area 
where  the  beating  action  is  most  intense,  or  by  inserting 
a  number  of  flat-headed  chaplet  nails  in  close  prox- 
imity at  that  area,  and  allowing  the  metal  to  fall  upon 
them. 

As  a  general  rule  it  may  be  stated  that,  unless  good 
reasons  exist  for  the  contrary  practice,  moulds  should  be 
poured  from  the  top.  Iron  falling  upon  liquid  iron  re- 
mains hotter  and  in  greater  agitation  than  iron  rising 
slowly.  The  latter  will  carry  up  the  scum  and  dirt  which 
it  gathers  from  the  sides  of  a  mould,  allowing  these 
foreign  matters  to  lodge  under  projecting  portions:  but 
the  metal  falling  from  above  cuts  up  the  dirt  and  scurf, 
keeping  them  in  such  perpetual  movement  that  they  can 
scarcely  effect  a  lodgement  in  the  mould.  Running  from 
the  bottom,  the  metal  becomes  chilled  as  it  rises;  but 
running  from  the  top,  the  last  iron  poured  is  as  hot  as 
the  first.  When  running  from  the  top  and  the  bottom  at 
once,  the  first  metal  is  led  in  at  the  bottom,  and  after  a 
portion  of  the  mould  is  filled,  the  top  metal  is  intro- 
duced, falling  upon  metal.  The  dirt  is  thus  cut  up  and 
the  iron  is  kept  hot  until  the  mould  is  filled.  No  set 
rules  can  be  laid  down  for  the  most  suitable  method  of 
pouring,  the  matter  is  entirely  one  for  the  exercise  of  the 
moulder's  judgement. 

Examples  of  the  simplest  forms  of  pouring  basins  and 
runners  occur  at  p.  141.  These  are  only  adapted  for  the 
smallest  moulds.  For  those  of  moderate  and  of  large 
dimensions,  the  forms  of  the  basins  and  the  modes  of 
running  are  modified.  The  shape  of  a  typical  pouring 
basin  and  runner  is  shown  in  Figs.  86  and  89,  pp.  165 
and  169.  Though  a  rough-looking  affair,  every  detail  is  a 


PRINCIPLES  OF  GREEN  SAND  MOULDING     153 

matter  of  design.  First  there  is  a  depression  at  0.  This 
receives  the  first  inflow  of  the  metal.  If  there  were  no 
such  depression  the  metal  on  being  poured  from  the  ladle 
would  flow  at  once  into  the  mould,  and  as  some  slight 
adjustment  of  the  ladle  is  necessary  before  it  is  ready  for 
emptying  a  full  stream,  a  few  drops  would  be  running 
in  during  the  making  of  such  adjustment.  These  would 
form  cold  shots  in  the  casting.  Also,  the  iron  falling  for 
a  considerable  time  upon  a  bed  of  sand  would  cut  it  up, 
and  wash  portions  into  the  mould.  But  the  depression 
in  the  basin  receives  and  retains  the  first  few  droppings 
of  metal,  and  forms  a  shallow  reservoir  into  which  all 
the  remaining  metal  falls  as  in  a  bath,  preventing  the 
cutting  up  of  sand.  Only  when  the  depression  is  filled 
does  the  iron  begin  to  flow  off  in  a  quiet  stream  into  the 
mould.  As  soon  as  the  depression  is  full  the  remaining 
metal  is  poured  very  rapidly  into  the  basin  until  it  is 
nearly  level  with  the  brim,  and  is  kept  filled  until  the 
mould  is  quite  full.  This  is  necessary  in  order  to  prevent 
any  dirt  or  scurf  which  may  happen  to  pass  the  skimmer 
from  entering  the  mould  with  the  metal.  As  long  as  the 
basin  is  full,  the  dirt  floating  on  the  surface  will  not  be 
carried  into  the  ingate.  For  a  similar  reason  the  surface 
area  of  the  depressed  portion  is  made  sufficiently  large. 
If  it  were  small  it  would  not  hold  much  metal,  and  the 
scurf  would  be  more  likely  to  become  sucked  into  the 
ingate. 

These  pouring  basins  are  made  chiefly  by  hand.  A 
small  middle  flask,  or  a  frame  only,  is  laid  upon  the 
cope,  and  swabbed  with  clay  water,  the  runner  pin  put 
in  place,  the  sand  rammed  with  a  pegging  rammer, 
central  portions  dug  out  and  then  rounded  and  moulded 
to  the  proper  form  with  the  hands.  All  sharp  corners 


154  PRACTICAL  IRON  FOUNDING 

which  might  become  washed  down  by  the  rush  or  pres- 
sure of  metal  are  scrupulously  avoided. 

In  spite  of  every  precaution  in  the  manner  of  pouring, 
particles  of  dirt  which  accumulate  from  the  metal  in  the 
ladle,  and  from  the  sand  in  the  basin,  gain  access  to  the 
irftmld.  In  castings  which  are  not  turned  or  planed, 
the  slight  contamination  thus  caused  is  not  of  import- 
ance ;  but  on  turned  or  planed  faces  the  slightest  specks 
have  an  unsightly  appearance,  and  in  such  work  various 
devices  are  made  use  of  to  obtain  the  cleanest  faces 
possible. 

In  steam  and  hydraulic  cylinders,  in  pumps,  and  work 
of  this  class,  a  belt  of  head  metal  is  cast  on,  into  which 
the  lighter  matters  rise,  and  this  is  subsequently  turned 
off.  On  large  flat  upper  surfaces  an  extra  thickness  of 
metal  is  allowed,  to  be  planed  off  afterwards.  Or,  several 
risers  are  placed  over  the  surface,  and  cut  off.  Lastly, 
the  mode  of  running  is  modified,  the  metal  being  led  in 
through  a  skimming  chamber.  This  method  is  shown  in 
Fig.  73.  Here  B  is  the  ingate,  and  (7,  D,  the  runner. 
Right  in  the  course  of  the  runner,  which  is  purposely 
made  of  the  indirect  form  shown  in  plan,  there  is  a 
capacious  chamber,  A,  made  by  ramming  up  a  ball  or  a 
disc  in  the  mould.  Over  the  chamber  is  a  riser,  E.  As 
the  metal  obtains  entry  through  the  first  portion,  <7,  of 
the  runner  into  the  side  of  this  chamber,  A,  it  receives  a 
rotary  motion,  as  shown  by  the  arrows  in  plan  view.  The 
effect  is  to  throw  the  heavy  metal  to  the  outer  part  of  the 
sphere,  leaving  the  scurf  and  inferior  lighter  metal  at 
and  about  the  centre.  The  outer  metal  passes  into  the 
mould  by  the  ingate  D,  F,  and  the  lighter  matters  float 
upwards  into  the  riser  E.  This  riser  need  not  be  added 
in  very  small  moulds,  the  chamber  in  itself  being  suffi- 


PRINCIPLES  OF  GREEN  SAND  MOULDING     155 

ciently  capacious;  but  in  large  moulds  enough  dirt  will 
accumulate  to  fill  it  up  to  the  brim.  Fig.  74  is  drawn  to 
show  by  contrast  with  Fig.  73  the  wrong  way  to  make  a 


PLAN  ONLINE  C.Q,, 

£•-.';>>' < •••.•":/;  ".'.v;'* 
2^&>:^\$fe«-.. 


G  — 


FIG.  73. — SKIMMING  CHAMBER. 


'•••-  -•«>,« 

FIG.  74. — INCORRECT  FORM  OF  SKIMMING  CHAMBER. 

skimming  chamber.    The  runner  entering  and  leaving 
the  chamber  in  a  straight  line,  F,  there  is  no  rotary 
motion  set  up  in  the  metal,  and  the  chamber  is  useless. 
Sometimes  a  disc  is  used  in  the  smaller  moulds  instead 


1.56 


PRACTICAL  IRON  FOUNDING 


of  a  ball.  The  workmen  usually  speak  of  the  employ- 
ment of  skimming  chambers  as  running  with  a  ball,  or 
running  ivitli  a  disc.  Figs.  75  and  76  show  the  pouring  of 
a  cylinder  cover  through  a  disc,  A.  B  is  the  ingate,  C 
and  D  risers,  C  being  over  the  disc  and  7)  over  the  casting. 

_/o\ 


V2/ 


FIG.  75. 


FIG.  76. 
POURING  A  CYLINDER  COVER. 

The  area  of  ingates  should  be  in  proportion  to  the  size 
of  the  castings.  Castings  are  light  or  heavy,  thick  or 
thin,  machined  or  left  rough,  and  all  these  points  have  to 
be  considered  in  determining  the  sizes,  positions,  and 
character  of  runners.  Thin  and  light  castings  should  be 
poured  from  several  thin  runners,  or  from  a  spray.  Fig. 


PRINCIPLES  OF  GREEN  SAND  MOULDING     157 


77  shows  a  thin  runner  stick  of  the  type  which  is  em- 
ployed for  pouring  thin  pipes,  etc.  A  heavy  runner  would 
draw  a  light  casting,  and  probably  cause  fracture.  The 
great  length  of  runner  is  given  to  compensate  for  its  nar- 
rowness, a  large  area  being  necessary  for  quick  running 
of  thin  castings.  Fig.  78  shows  a  pattern  spray  of  run- 
ners, A,  ready  for  ramming  in  situ,  against  pattern  B, 
also  used  for  the  pouring  of  thin  light  castings,  the  total 
area  of  entry  being  large,  while  the  spray  itself  is  readily 


FIG.  77.  —  EUNNER  STICK. 


FIG.  79. — RUNNER 


FIG.  78.—  SPRAY. 

detachable  after  casting.  Although  heavy  castings  will 
require  runners  of  large  area,  it  is  better,  as  far  as  prac- 
ticable, to  employ  several  runners  of  moderate  area 
rather  than  one  or  two  of  large  size.  Thus  the  runner 
pin  shown  in  Fig.  79,  which  is  the  most  common  form, 
is  not  so  good  as  the  oblong  ones  in  Figs.  80  to  82,  being 
liable  to  cause  a  draw  in  its  immediate  vicinity.  Kunners 
of  circular  section  are  most  often  used,  but  those  of  flat 
and  oblong  section  are  in  many,  perhaps  in  most  cases, 
preferable  to  the  round  ones,  because  they  are  more 


158 


PRACTICAL  IRON  FOUNDING 


easily  and  safely  knocked  off  and  chipped  from  the  cast- 
ing. There  must  in  any  case  be  sufficient  area,  because  a 
casting  poured  too  slowly  will  probably  show  cold  shuts, 
that  is,  imperfect  union  of  the  metal  in  some  sections.  A 
mould  poured  too  rapidly  will  become  unduly  strained, 
and  perhaps  blown  and  scabbed.  A  light  thin  casting 
cannot  be  poured  too  rapidly  or  the  metal  be  too  hot;  a 


ffl 


SfcCTIONON  LINE.C.C, 
FIG.  80. 


INGATES  AND  RUNNERS. 


FIG.  81. 


heavy  casting  must  be  poured  slowly,  and  the  metal  must 
be  dead. 

In  cases  where  castings  have  to  be  machined  the  run- 
ners should  be  kept  as  far  away  as  possible  from  the 
machined  parts,  as  the  metal  is  always  dirty  and  spongy 
in  the  immediate  vicinity  of  a  runner. 

Figs.  80  to  82  illustrate  two  examples  of  running  at  the 
side  of  a  mould.  In  each  case  A  is  the  ingate  and  B  the 


PRINCIPLES  OF  GREEN  SAND  MOULDING     159 


runner.  The  pattern  ingate,  and  the  pattern  runner  are 
each  rammed  up  in  place,  and  the  runner  B  in  Fig.  80 
is  then  withdrawn  into  the  mould  in  the  direction  of  the 
arrow.  In  Fig.  82  the  runner  stick  is  drawn  in  the  oppo- 
site direction,  the  sand  being  temporarily  dug  away  be- 
hind for  the  purpose.  Fig.  81  shows  a  loam  cake,  D, 
rammed  in  the  mould,  being  better  adapted  than  green 
sand  in  a  heavy  mould,  to  withstand  the  cutting  action 
of  the  iron  as  it  passes  from  A  into  B. 

Fig.  170,  p.  251  illustrates  the  pouring  of  a  large  mould, 
suitable  also  for  cylinders 
cast  on  end,  through  an  an- 
nular pouring  basin.  The 
metal  is  poured  in  the  de- 
pression L  at  the  right 
hand,  whence  it  overflows 
into  the  annular  basin,  and 
then  falls  through  the 
runner  passages  disposed 
around  the  basin.  After 
the  mould  is  filled,  any 
surplus  metal  runs  off  at  M. 

Fig.  83  shows  the  external  appearance  of  a  mould  after 
it  has  been  poured.  Here  A,  A  are  the  pouring  basins  for 
the  ingates,  B,  B  are  the  flow-off  gates.  The  drawing 
shows  the  blue  hydrogen  flames  all  over  the  top  and  at 
the  joint. 

Feeding. — A  draw  (see  p.  128)  occurs  because  the  sum 
total  of  shrinkage  will  be  greatest  where  the  greatest  mass 
of  metal  is  situated.  Since  the  outer  skin  becomes  chilled 
by  contact  with  the  sand  and  sets  first,  nearly  all  the 
later  shrinkage  goes  on  within  the  mass,  and  this 
naturally  will  produce  a  spongy  and  open  casting.  To 


FIG.  82. — INGATE  AND 
RUNNER. 


160  PRACTICAL  IRON  FOUNDING 

prevent  this,  the  casting  is  fed.  In  some  cases  the  head 
cast  on  to  receive  the  scurf  or  sullage  is  made  suffici- 
ently large  and  massive  to  do  duty  as  a,  feeder  head.  The 
mass  of  metal  which  it  contains  must  then  be  sufficient 
not  only  to  remain  liquid  until  after  the  metal  in  the 
mould  has  set,  but  also  to  exert  considerable  pressure 
upon  the  mould,  feeding  and  consolidating  at  the  same 
time. 

A  feeder  liead  proper,  however,  is  distinct  from  head 
metal,  consisting  of  a  basin  or  cup  of  metal  somewhat 


7          "        '  ,    1  

''siZ/*;.*  -'/>;  'j^^'^>'i^/&*/zZ¥s 

FIG.  83. — RUNNERS  AND  RISERS. 

like  a  pouring  basin,  in  fact  a  pouring  basin  is  often 
utilized  as  a  feeder  head,  as  in  Fig.  84.  A  feeder  head 
must  be  placed  directly  over  that  particular  portion, 
boss,  lug,  etc.,  the  shrinkage  of  the  mass  in  which  it  is  in- 
tended to  compensate,  and  its  capacity  must  be  so  great 
that  its  metal  shall  remain  fluid  after  that  in  the  boss, 
lug,  etc.,  has  set. 

The  feeding  or  pumping  is  performed  by  getting  a  -J-  in. 
or  f  in.  iron  rod  red  hot  in  the  molten  metal  in  the  ladle, 
and  immediately  the  pouring  has  taken  place  the  rod  is 
inserted  into  the  feeder  head,  Fig.  84,  and  a  vertical  up- 


PLATE  V 


FIG.  187. — PATTERN  PLATE  AND  MOULDS  OF  EAILWAY  WHEEL. 
LANCASHIRE  AND  YORKSHIRE  EAILWAY 


FIG.  188. — A  PATTERN  PLATE 


Seep.M8  \Fanngp.  10 

FIG.  189. — McPnEE  PATTERN  PLATES 


PRINCIPLES  OF  GREEN  SAND  MOULDING     161 


and-down  movement  of  the  rod  in  the  metal  is  com- 
menced, taking  care  not  to  touch  the  actual  mould.  The 
effect  is  to  create  an  agitation  or  movement  in  the  molten 
metal,  and  to  keep  a  passage  clear  into  the  heavy  and 
still  molten  central  mass,  in  order  that  until  it  becomes 
actually  set,  fresh  and  ample  supplies  of  hot  metal  shall 
enter  from  the  feeder  head  to  compensate  for  the  loss 
due  to  interior  shrinkage.  In  large 
masses  it  is  necessary  to  supply 
added  hot  metal  from  a  hand  ladle 
to  the  feeder  head.  The  pumping 
continues  until  the  metal  thickens 
and  clings  to  the  rod,  when  the 
latter  is  struck  sharply  with  a  bar 
of  iron  or  hammer  to  effect  the  de- 
tachment of  the  clinging  portions. 


FIG.  84. — FEEDING. 


FIG.  85. — FLOW-OFF  GATE. 


Finally  the  metal  becomes  so  viscous  that  little  more 
shrinkage  will  take  place,  and  the  feeding  ceases. 

Risers. — In  moulds  of  considerable  area,  risers  or  flow- 
off  gates  are  employed.  Their  function  is  mainly  to  relieve 
the  cope  of  excessive  strain,  which  in  their  absence 
would  cause  injury  to  the  mould.  There  is  an  enormous 
pressure  on  a  cope  of  several  square  feet  in  area,  and 
though  the  flasks  are  made  stiff  and  strong,  and  well 

M 


162  PRACTICAL  IRON  FOUNDING 

loaded,  this  pressure  would,  and  often  does,  cause  a 
thickening  of  the  central  portions  of  the  castings  to  an 
extent  of  |  in.  or  £  in.,  due  to  the  rising  up  or  springing 
of  the  cope  under  pressure.  Eisers  relieve  it  partly,  though 
not  entirely,  of  pressure,  but  they  also  allow  of  free  exit 
of  the  air  and  gas,  which  would  otherwise  be  confined  in 
the  mould,  and  cause  scabbing.  The  risers  should  pro- 
perly be  kept  closed  with  plugs  of  clay  or  sand  until  the 
mould  is  just  upon  the  point  of  filling,  when  the  plugs 
are  instantly  removed,  and  the  pouring  still  continuing, 
the  excess  of  metal  is  allowed  to  flow  off  quietly  outside 
the  flask.  Fig.  85  shows  one  of  these  flow-off  gates,  the 
metal  flowing  away  over  the  sloping  bank  of  sand. 


CHAPTEK  IX 

EXAMPLES  OF  GREEN  SAND  MOULDING 

WE  are  now  in  a  position  to  consider  some  examples  of 
green  sand  moulding  affording  illustrations  of  the  varied 
work  which  calls  forth  the  best  judgment  of  the  jobbing 
moulder.  Figs.  86  to  89  are  illustrations  of  the  mould 
made  for  an  anvil  block  of  four  tons  weight.  It  is  an 
example  of  a  deep  and  heavy  mould.  Though  this  is  not 
a  case  of  bedding-in,  pure  and  simple,  it  illustrates  the 
manner  in  which  methods  are  modified  in  order  to  suit 
individual  and  special  jobs. 

To  begin,  the  top  of  the  block  must  be  sound,  and  that 
is  therefore  cast  in  the  bottom.  It  is  a  deep  mould,  and 
there  is  a  core,  A,  in  the  bottom  for  the  anvil,  there  is 
also  a  great  discrepancy  in  the  dimensions  of  the  smaller 
part  of  the  block  B,  on  which  the  anvil  rests,  and  the 
base  C,  which  is  embedded  in  concrete.  For  these  reasons 
the  method  of  making  the  mould  which  is  here  shown 
was  adopted.  The  whole  of  the  stem  B  was  made  in  flasks 
in  dry  sand.  The  method  of  supporting  the  sand  in 
middle-part  boxes  by  means  of  rods  and  lifters  is  shown 
in  perspective  in  Fig.  87.  The  flask  D  was  parted  from  E 
at  the  joint  a — a,  for  convenience  of  placing  the  core  A 
in  position,  but  E,  F,  G  were  permanently  cottared  to- 
gether to  form  one  middle.  Blocks  of  wood  were  neces- 
sarily interposed  between  E  and  F,  to  allow  of  the  entrance 
of  the  runner  N'  to  the  mould.  This  portion  of  the  mould 

163 


164  PRACTICAL  IRON  FOUNDING 

was  made,  dried,  cored,  and  finished  first.  Then  a  pit  was 
dug  in  the  foundry  floor,  a  coke  bed,  //,  laid  down  at  the 
proper  depth,  sand  rammed  and  vented  over  it,  and  the 
box  parts  D,  E,  F,  G  all  cottared  together,  were  bedded 
down  level  thereon,  their  vents  passing  down  to  the  coke 
bed  H,  and  thence  out  through  the  vent  pipes  /,  which 
are  rough  pieces  of  cast  iron  pipe  of  3  in.  or  4  in.  dia- 
meter, reaching  from  the  bed  to  the  surface  of  the  floor. 
The  space  encircling  the  flasks  was  then  filled  with  sand, 
and  flat-rammed  level  with  the  top  edge  L.  The  pattern 
being  jointed  at  J  and  at  K ,  as  a  matter  of  convenience, 
the  portion  from  J  to  K  was  placed  back  in  the  mould, 
and  the  base  C,  dowelled  by  the  face  K,  was  laid  in  posi- 
tion for  ramming,  which  ramming  was  continued  to  the 
top  edge  L. 

The  cope  M  being  perfectly  plain  was  not  rammed  in 
place,  but  upon  a  levelled  bed  of  hard  sand,  being  liftered 
and  vented  all  over  its  depth  and  area.  A  few  lifters 
depending  from  their  bars  are  shown  in  section  at  M',  to 
illustrate  the  method  of  liftering.  While  the  vents  from 
the  stem  B  go  down  into  the  coke  bed  J7,  those  from  the 
base  C  pass  out  through  the  cope  M. 

The  manner  of  pouring  was  as  follows.  There  was  one 
pouring  basin,  Ar,  for  running  near  the  bottom,  and  one, 
O,  for  the  main  running  at  the  top.  The  purpose  of  the 
runner  N'  is  simply  to  fill  the  lower  part  of  the  mould,  so 
that  the  metal  falling  from  the  top  at  0'  shall  not  cut  up 
the  sand,  but  fall  into  a  pool  of  metal.  A  four  ton  ladle 
was  used  at  0,  and  a  one  ton  at  N,  thus  allowing  a  ton 
for  heads  and  basins.  The  pouring  commenced  at  0,  but 
merely  to  steady  the  ladle  in  position,  and  fill  the  hollow, 
0,  of  the  basin.  As  soon  as  this  was  done,  the  ladle  at 
N  was  poured,  the  plug  P  being  kept  in  place  until  the 


166  PRACTICAL  IRON  FOUNDING 

basin  was  nearly  full,  when  P  was  removed,  and  the 
metal  entered  the  mould.  Immediately  it  had  entered, 
the  filling  of  pouring  basin  0  began,  and  when  nearly 
level,  its  plugs,  P',  were  removed,  and  the  metal  was  run 
into  the  mould  rapidly.  The  fact  of  its  being  filled  was 
indicated  by  the  flow-off  at  the  risers  Q,  the  plugs  for 
which  (not  shown)  were  removed  at  that  instant.  After 
the  cast,  feeding  was  performed  at  the  feeder  head,  11. 
The  area  of  the  runner  N'  was  3  in.  x  1  in.,  that  of  0',  (/, 
6  in.  x  1|  in.  At  the  opening  of  each  ingate,  N"  and  0", 
loam  cakes  were  imbedded  in  the  pouring  basins  to  sus- 
tain the  pressure  of  the  metal,  sand  being  liable  in  heavy 
casts  to  become  cut  up  and  washed  away.  The  object 
of  the  flasks  S,  enclosing  the  ingate  N",  at  the  section 
where  the  ingate  comes  in  very  close  proximity  to  the 
base,  is  to  prevent  a  probable  washing  away  of  the  inter- 
vening sand,  T,  which  is  a  casualty  to  be  guarded  against. 
The  pressure  is  in  such  cases  enormous. 

To  avoid  confusion,  no  weights  are  shown  on  the  cope. 
By  calculation  the  pressure  on  the  cope  should  be  as 
follows : 

Area  of  surface  C,  Figs.  86  and  88,  5  ft.  0  in.  x  4  ft. 
6  in.  Height  from  face  of  cope  to  level  of  pouring  basin, 
about  18  in.  Then  60  in.  x  54  x  18  =  58320  in.  58320  in.  x 
•263  =  15338  Ib.  15338  lb.  =  6  tons  18  cwt.,  statical  load 
required,  including  cope.  Actually  8  tons  of  weights  were 
used. 

The  flywheel  mould  shown  in  the  succeeding  figures 
is  an  example  of  a  type  of  work  by  which  the  cost  of 
pattern-making  is  much  lessened.  Instead  of  making  a 
complete  pattern,  a  process  of  sweeping  up  and  of  sec- 
tional moulding  is  adopted.  It  cannot  properly  be  called 
bedding  in,  because  there  is  no  pattern,  neither  does  it 


HH 


S&i 


FP 
o 


feS^^lpl^m   » 


i^WK-;'\^:;:K:$i&    * 
ClSliiiy^^!^    § 


i    «         £fi 


kOK^M;^K^«    5 

iMii^MMK»  § 


168  PRACTICAL  IRON  FOUNDING 

come  under  the  head  of  turning  over.  It  resembles  in 
the  main  bedding  in,  even  though  there  is  no  complete 
pattern  used,  because  the  work  is  moulded  in  the  floor, 
and  a  cope  is  the  only  flask  used.  The  method  is  one 
which  is  often  adopted  in  heavy  work  of  this  general 
type,  such  as  rectangular  bed  plates,  and  circular  bases, 
even  when  the  internal  portions  happen  to  be  somewhat 
intricate,  intricate  portions  being  readily  formed  by 
means  of  cores. 

A  coke-bed  should  properly  be  laid  down  for  this,  un- 
less the  rim  happens  to  be  narrow,  in  which  case  venting 
over  the  bottom,  and  diagonal  venting  therefrom  to  the 
mould  joint  will  answer  the  purpose.  In  any  case  the 
cope  is  rammed  before  the  lower  face  is  touched,  as 
follows : 

A  bed  of  sand  is  rammed  hard,  and  levelled  with  the 
foundry  floor,  and  the  striking  board  A,  Fig.  90,  is  at- 
tached to  the  strap  B  and  the  striking  bar  C,  the  socket 
D  of  which  is  bedded  in  the  floor.  By  comparing  the  edge 
of  this  board  with  the  pattern  segment,  Fig.  91,  its  coin- 
cidence with  the  edge  of  the  segment  is  apparent.  The 
board  therefore  strikes  a  reverse  mould,  upon  which  the 
cope,  Fig.  92,  is  laid  and  rammed,  a  stratum  of  parting 
sand  intervening.  The  reason  why  this  method  is  adopted, 
instead  of  striking  the  cope  direct,  is  that  the  precise 
ultimate  position  of  the  cope  for  casting  is  secured 
thereby.  If  the  cope  were  struck  separately,  and  put  in 
place  by  measurement,  it  would  be  much  more  trouble- 
some to  set  it  with  accuracy  than  when  it  is  rammed  in 
place;  for  it  is  not  a  case  of  fitting  of  flasks  with  pins. 
The  cope  has  to  be  laid  upon  the  floor,  and  then  the  only 
setting  which  is  available  is  that  done  with  stakes  of 
iron  driven  into  sand,  Fig.  97,  D.  Returning  the  cope  to 


i .  -  '     2 


170 


PRACTICAL  IRON  FOUNDING 


its  original  position  by  means  of  the  stakes  with  which 
it  was  set  for  ramming,  is  simpler  and  far  more  accurate 
than  striking  it  first  and  setting  it  afterwards.  Before 


FIG.  90. — TOP  STRIKING  BOARD  FOR  FLYWHEEL. 

the  cope  is  rammed  upon  the  bed  several  things  have  to 
be  noted. 

Looking  at  the  section  through  the  flywheel  rim,  Fig. 


FIG.  92.— COPE. 

93,  it  is  clear  that  the  formation  of 
the  face  of  the  cope  must  take  one  of 
two  directions.    It  must  either  coincide 
with  the  upper  face,  A,  of  the  rim, 
FIG.  91.— PATTERN   and  with  the  horizontal  central  plane, 
SEGMENT.  B,  of  the  bosses,  or  it  must  remain 

entirely  continuous  with  the  rim  face, 
A,  A'.  The  choice  between  the  two  methods  is  de- 
termined by  the  formation  of  the  upper  halves  of  the 
bosses,  and  of  the  prints  which  carry  the  arms.  If  the 


EXAMPLES  OF  GREEN  SAND  MOULDING  171 

mould  joint  were  shouldered  down  to  be  continuous 
with  the  centres,  B,  of  the  bosses,  then  Fig.  94  would 
show  the  joint  face  in  section,  and  then  it  is  evident 
that  as  many  half  bosses  and  half  prints  as  there  are 
bosses  and  arms  in  the  wheel  would  have  to  be  laid 
upon  the  reverse  sand  bed  struck  by  the  board  A  in  Fig. 
96,  and  in  precise  coincidence  with  the  positions  which 
the  lower  halves  of  the  bosses  and  prints  are  afterwards 
to  occupy,  and  that  the  cope  would  be  rammed  over  them. 
It  would  not  be  easy  to  set  these  bosses  correctly.  Nor 
is  it  advisable  to  lift  the  cope  sand  away  from  a  deep 
shoulder,  A,  Fig.  94,  such  as  that  against  which  the 


A  --- 


FIG.  93.—  SECTION  FIG.  94. — ALTERNATIVE 

OF  KIM.  JOINTING  OF  COPE. 

bosses  would  have  to  abut.    Hence  the  reason  for  the 
adoption  of  the  method  illustrated  in  these  figures. 

The  lower  halves  of  the  bosses  within  the  rim  are 
formed  by  ramming  directly  from  the  pattern  segment, 
Fig.  91.  The  upper  halves  are  made  in  cores,  the  out- 
lines of  which  are  shown  dotted  in  Fig.  93.  In  this  case, 
to  give  sufficient  sand  in  the  core  above  the  beading 
on  the  boss,  it  happens  to  be  necessary  to  increase  the 
height  beyond  that  of  the  top  face  of  the  rim.  This 
slightly  complicates  matters,  because  the  thickness  of  the 
core  C,  Fig.  93,  standing  above  that  face,  has  to  enter 
into  a  corresponding  print  in  the  cope.  Hence  six 
prints  of  thickness  C,  and  of  the  same  length  and  breadth 
as  the  core,  have  to  be  measured  carefully  into  place  on 
the  reverse  bed  struck  by  the  board  A,  Fig.  90,  in  order 


172 


PRACTICAL  IRON  FOUNDING 


that  their  impressions  may  be  imparted  to  the  cope 
sand  at  the  time  of  ramming  the  latter.  These  prints 
are  shown  in  section,  Fig.  92,  jB,  and  in  plan,  Fig.  95. 
They  are  set  by  a  circle  corresponding  in  diameter  with 
that  of  the  inside  of  the  rim,  and  their  centre  lines  are 
made  to  coincide  with  the  intended  centre  lines  of  the 
arms  marked  upon  the  bed.  They  are  prevented  from 


FIG.  95.— TOP  PRINTS. 

becoming  shifted  during  the  process  of  ramming,  by  means 
of  common  cut  nails  driven  down  alongside  of  them  into 
the  sand.  In  this  position  they  are  rammed  and  their 
impressions  obtained  in  the  cope.  The  cope  is  liftered, 
Fig.  92,  rammed,  and  vented  precisely  as  though  it  were 
above  a  pattern,  and  it  is  then  lifted  off,  taken  away, 
turned  over,  and  any  broken  edges  mended  up. 

Then  the  second  striking  board  B,  Fig.  96,  is  bolted  to 


EXAMPLES  OF  GREEN  SAND  MOULDING     173 

the  strap  at  such  a  height  that  its  joint  edge  A  coincides 
with  the  joint  edge  E  in  Fig.  90.  The  lower  edge  C  coin- 
cides with  the  lower  face  of  the  rim,  so  forming  the  bed 
upon  which  the  pattern  segment,  Fig.  91,  is  to  rest.  The 
corner  D  coincides  with  the  external  diameter  of  the  rim, 
as  shown  dotted;  or  it  may,  if  preferred,  be  of  a  larger 
diameter.  The  edge  of  which  D  is  the  termination,  is 
made  diagonal,  because  if  made  perpendicular  the  sand 
would  tumble  down — being  made  as  it  is,  the  segment 
pattern,  Fig.  91,  rests  upon  the  bed  struck  by  C,  and  the 
sand  is  rammed  both  on  the  external  and  internal  sweeped 


,   ••  .      .        .  . 

'-Iv^^-^V  f'V*"'^  ''•".'•'  »'•*';••'•".  •••?•.'•>•'•••/>  c.  '.'.•'•>•:  •,-".-• 

,   '„•'•;»  •'•,'"»'  S    ^  '  "°-°  •  .  -  '  ''•  "'•'  -c'-i'-d  i*-f  r^l~>o 


y-  _  _  ^ 

FIG.  96.  —  BOTTOM  STRIKING  BOARD. 

faces  of  the  segmental  pattern.  The  position  which  the 
segment  has  to  occupy  in  relation  to  the  swept-up  bed  is 
shown  by  its  dotted  outline  given  in  the  figure.  The 
edge  E,  it  will  be  seen,  corresponds  with  the  upper  face 
of  the  rim. 

The  bed  is  made  as  though  for  a  bedded-in  mould. 
The  sand  is  rammed  hard  in  the  lower  portions  and  well 
vented,  and  the  vents  closed  with  the  fingers.  A  more 
open  stratum  of  about  an  inch  in  thickness  is  lightly 
rammed  over  this  surface  and  consolidated  with  the 
fingers,  the  board  being  swept  around  several  times 
until  an  evenly  rammed,  well-  vented,  and  smooth  bed 


174 


PRACTICAL  IRON  FOUNDING 


is  produced  underneath  those  portions  which  will  be  oc- 
cupied with  the  rim,  and  to  a  little  distance  without  and 
within  the  same.  Then  the  board  is  removed  and  the 
pattern  segment  laid  down  for  ramming.  This  segment, 
Fig.  91,  has  the  same  section  as  the  rim.  Two  half 
bosses,  A,  Ay  are  fastened  upon  it  very  exactly  at  one- 


&'&«ttft 


FIG.  97. — PLAN  OF  MOULD. 

sixth  of  the  circumference.  Prints  B,  B  occupy  the 
positions  of  the  complementary  halves.  Ample  taper  is 
given  to  these  prints,  as  shown.  The  segment  is  laid  in 
the  position  seen  dotted  in  Fig.  96,  and  rammed.  The 
circumferential  position  of  the  segment  at  each  remove 
is  governed  by  the  bosses,  the  boss  near  one  end  being 
dropped  into  the  impression  just  made  by  its  fellow  at 
the  end  opposite.  The  precise  length  of  the  segment 


EXAMPLES  OF  GREEN  SAND  MOULDING     175 

extending  beyond  the  bosses  is  not  of  importance.  It  is 
not  at  all  necessary  to  ram  the  sand  over  the  whole  of  the 
internal  area,  but  only  sufficiently  far  inwards  to  afford 
a  backing  for  the  rim  mould,  and  for  the  bosses  and 
their  prints.  This  is  seen  in  Fig.  97.  At,  and  near  the 
centre  also,  a  space  must  be  left  for  the  small  flask 
containing  the  boss  mould. 

We  now  leave  the  rim  for  awhile,  to  note  the  prepara- 


FIG.  98. — Boss  MOULD. 

tion  of  the  boss.  This  is  rammed  from  a  complete  pat- 
tern in  a  small  flask  by  itself.  Fig.  98  shows  the  joint 
face  of  the  lower  half  of  this  flask  in  plan.  As  the  arms, 
which  are  cast  in,  have  to  come  through  the  flask  joints, 
these  joints  are  left  open  to  an  amount  sufficient  for  that 
purpose,  blocks  of  wood,  A,  being  inserted  at  the  corners 
at  the  time  of  ramming,  to  keep  the  flasks  at  the  required 
distance  apart.  The  sand  therefore  stands  above  the 
joint  faces  of  the  flasks  in  both  top  and  bottom  parts, 
reaching  to  the  centre  of  the  arms.  This  explains  the 


176  PRACTICAL  IRON  FOUNDING 

reason  of  the  sloping  joint  indicated  by  the  shading. 
The  ramming  up  is  quite  simple,  and  is  done  in  dry 
sand. 

After  the  boss  mould  is  dried,  it  is  set  in  the  centre  of 
the  rim  mould,  Fig.  97,  its  position  being  checked  both 
radially  and  horizontally,  the  rule,  straightedge,  and 
spirit-level  being  used,  and  the  print  impressions  for  the 
arms  in  rim  and  boss  are  all  brought  in  line. 

The  cores  which  form  the  upper  halves  of  the  bosses 
are  made  in  the  box,  Fig.  99. 

The  arms  are  formed  of  malleable  iron  bar  cut  off  in 
suitable  lengths,  and  either  jagged,  or  fullered,  Fig.  100, 


aram 

FIG.  99. — CORE  Box.         FIG.  100. — FULLERING  OF  ARM. 

near  the  ends,  to  render  their  hold  more  secure  than  it 
would  be  if  left  smooth. 

They  are  now  set  in  their  places,  both  in  the  boss  and 
rim,  Fig.  97,  A,  A  showing  the  relative  positions  of  arms 
and  mould  at  this  precise  stage.  All  being  thus  set  in, 
the  cores  forming  the  top  halves  of  the  bosses  are  laid  in 
their  prints,  Fig.  97,  one,  C,  being  shown  in  place  over  the 
arm  B.  Then  the  cope  being  returned  to  the  position  in 
which  it  was  rammed,  by  means  of  the  guidance  afforded 
by  the  stakes,  Fig.  97,  D,  these  cores  are  confined 
securely,  their  upper  portions,  of  the  thickness  C  in 
Fig.  93,  entering  into  the  impressions  formed  by  the 
prints  in  Fig.  92,  B,  and  in  Fig.  95.  This  particular 
example  illustrates  a  7  ft.  flywheel,  of  14  cwt.,  and  six 
tons  of  weights  were  used  on  the  cope.  The  pouring 


o 
O 
q 


^  w 


w 


EXAMPLES  OF  GREEN  SAND  MOULDING     177 

took  place  at  two  basins,  and  the  metal  was  fed  at  four 
risers. 

The  casting  of  the  boss  must  not  be  done  at  the  same 
time  as  that  of  the  rim.    If  it  were,  the  boss  being  small 


FIG.  101. --CENTRE  CROSS  CASTING. 

would  cool  at  once,  and,  setting  firmly,  oppose  the 
inward  shrinkage  of  the  rim  by  setting  up  the  resistance 
of  the  rigid  arms  thereto;  and  the  consequence  would 
be  that,  since  shrinkage  must  occur  somewhere,  the  rim 
would  become  fractured.  In  this  case  the  rim  was  cast 


178 


PRACTICAL  IRON  FOUNDING 


twenty-four  hours  before  the  boss,  and  when  its  shrinkage 
had  very  nearly  ceased  the  boss  was  poured.  It  was 
both  poured  and  fed  through  the  ingate. 

The  casting  in  Fig.  101  was  moulded  without  a  com- 
plete pattern,  three  of  them  being  made  by  the  methods 
to  be  described.  It  formed  the  base  or  pivot  upon  which 
the  superstructure  of  a  big  crane  revolved.  Fig.  101  shows 
the  casting  in  elevation  and  in  plan.  The  central  boss  A, 
being  large,  2  ft.  in  diameter  by  4  ft.  8  in.  long,  would 
have  been  an  expensive  job  to  lag  up  in  wood.  It  was 


FIG.  102. — SWEEPING  BOARD 
FOR  Boss. 


FIG.  103. — LOAM  MOULD 
FOR  Boss. 


therefore  struck  up  in  loam  and  sunk  into  the  floor  pre- 
viously to  the  ramming  up  of  the  cross.  Fig.  102  shows  the 
board  used  for  striking  the  boss,  and  Fig.  103  the  loam 
mould  of  the  same.  The  part  A  in  Fig.  102  strikes  the 
straight  part  2  ft.  in  diameter,  the  part  11  strikes  the 
collar;  the  length  of  C  is  equal  to  the  length  C,  4  ft. 
8  in.  in  Fig.  101,  and  D  strikes  a  print  for  the  end  D  of 
the  central  core  E. 

The  loam  mould  of  the  boss  is  built  up  of  bricks 
laid  radially.  One  course  is  sufficient,  because  although 
the  strain  on  the  mould  when  pouring  is  great,  the  bricks 
are  rammed  tightly  round  with  sand.  When  the  mould 


EXAMPLES  OF  GREEN  SAND  MOULDING     179 

of  the  boss  is  struck  and  dried,  it  is  set  in  its  permanent 
position,  and  before  it  is  rammed  around,  the  top  is 
levelled.  A  parallel  straight-edge  is  placed  across  the 
face  E  and  a  level  is  tried  upon  it.  The  straight-edge  is 
laid  in  different  directions  in  turn,  and  adjustments  of 
the  mould  are  made,  until  it  is  horizontal.  If  this  were 
not  done  carefully,  the  boss  would  be  cast  out  of  truth. 

Before  commencing  to  ram  the  cross,  coke  beds  have 
to  be  laid  down  underneath  the  horizontal  flat-plated 
portions  of  the  pattern  (see  Fig.  108,  p.  183).  Coke  or 
cinders  are  laid  down  there  to  a  depth  of,  say,  5  in.  or 


FIG.  104. — HALF  PATTERN. 

6  in.,  and  covered  with  an  inch  or  two  of  hay.  It  is  not 
necessary  to  lay  these  down  beyond  the  area  of  the  plates. 
Their  purpose  is  to  receive  the  vents  that  go  down  from 
the  flat  webs.  Vent  pipes  are  brought  up  obliquely  from 
the  beds,  one  from  each  bed  .at  the  outer  end.  These 
details  are  seen  in  Fig.  108. 

The  half  pattern  from  which  the  cross  is  moulded  is 
shown  in  plan  in  Fig.  104,  the  timber  shading  indicating 
how  it  is  constructed.  The  vertical  ribs  are  screwed  upon 
the  plated  portion,  the  screws  passing  through  the  plate 
so  that  they  can  be  removed  when  the  pattern  is  rammed 
up.  The  strips  that  form  the  plate  are  halved  together 


180 


PRACTICAL  IRON  FOUNDING 


next  the  boss.  The  pieces  which  form  the  broad  feet 
are  glued  and  screwed  on  separately,  and  their  brackets 
also.  The  half  boss  is  formed  of  two  pieces  fitted  be- 
tween the  vertical  ribs.  The  top  face  of  the  boss  on  the 
pattern  terminates  with  the  line  x — x  in  Fig.  101,  which 
is  coincident  with  the  top  face  of  the  loam  mould. 

The  coke  bed  having  been  laid  down,  sand  is~thrown 


6> 


FIG.  105. —  SETTING  PATTERN  INTO  MOULD. 

loosely  all  over  it  with  the  shovel,  up  to  about  a  suit- 
able level  for  bedding  the  pattern  into.  The  latter  will 
have  to  be  tried  in  two  or  three  times  until  it  has  a 
good  bedding  in  the  sand,  and  with  enough  sand  around 
its  edges  to  hold  it  securely  in  place.  At  this  stage,  and 
before  the  bulk  of  the  ramming  is  done,  it  is  levelled 
carefully  and  set  centrally  upon  the  loam  mould  of  the 
boss.  It  is  levelled  by  laying  a  parallel  straight-edge  A, 


EXAMPLES  OF  GREEN  SAND  MOULDING    181 

Fig.  105,  across  it  in  various  directions  in  turn,  and 
placing  a  level  upon  the  straight-edge.  According  to 
the  indications  of  the  level,  one  portion  of  the  pattern 
is  heaten  down  and  another  raised  up  by  tucking  sand 
underneath,  until,  in  whatever  direction  the  straight- 
edge and  level  are  placed,  the  level  shows  the  horizontal 
truth  of  the  pattern. 

The  half  pattern  is  set  centrally  by  laying  a  straight- 
edge B  along  the  centre  of  the  loam  mould  C  of  the 
boss,  and  bringing  the  central  joint  edge  of  the  half 
pattern  up  to  the  edge  of  the  straight-edge.  The  half 
pattern  is  now  ready  to  be  completely  rammed. 

Obviously,  in  a  case  like  this  the  sand  cannot  be  rammed 
underneath  the  flat  plate.  The  latter  is  therefore  un- 
screwed from  the  vertical  ribs  at  an  early  stage  of  the 
ramming,  which  is  easily  done,  because  all  the  screws 
which  hold  the  two  together  are  put  in  through  the 
plate  into  the  ribs.  This  plate  is  unscrewed  as  soon  as 
sufficient  sand  has  been  rammed  around  the  ribs  and  the 
boss,  in  order  to  prevent  the  possibility  of  their  being 
moved  out  of  place  by  further  ramming.  The  ramming 
is  then  completed  in  detail  up  to  the  Ifivel  of  the  under 
face  of  the  plate,  the  sand  being  strickled  off  level  with 
that,  the  top  edges  of  the  ribs  furnishing  the  guides  for 
the  operation.  Before  the  strickling  off  is  done,  the 
vents  are  carried  down  to  the  coke  bed  beneath,  a  long 
-jV  in.  or  §  in.  vent  wire  being  used.  These  vents  are 
pierced  pretty  thickly,  say  1  in.  apart,  going  from  the 
top  of  the  mould  down  to  the  cinders.  These  are  carried 
all  over  the  area  covered  by  the  plate,  and  some  are 
taken  down  a  little  way  outside  the  ribs.  Then  the  sand 
is  finally  tried  over  with  the  fingers,  the  damaged  faces 
made  good,  and  the  whole  strickled  over  level  with  the 


182 


PRACTICAL  IRON  FOUNDING 


tops  of  the  ribs.  Finally  the  plate  is  screwed  on  in 
place,  and  the  ramming  is  carried  up  to  its  edges  and 
to  its  top  face.  As  there  is  a  good  depth  of  sand,  in 
consequence  of  the  depth  of  the  ribs,  rods  are  driven 
down,  going  well  into  the  bed  below  to  support  the  sand. 


O 


FIG.  IOC}. — SETTING  PATTERN  FOR  SKCOND  PORTION 
OF  MOULD. 

At  this  stage  it  is  most  convenient  to  ram  the  cope. 
This  is  perfectly  plain,  so  that  it  might  be  rammed  on 
any  levelled  bed  away  from  the  pattern;  but  it  is  better 
to  ram  it  over  the  half  pattern,  because  the  cope  can  be 
returned  into  its  position,  guided  by  the  stakes,  with  the 
top  print  impression  central.  To  ram  the  cope  in  position, 


EXAMPLES  OF  GREEN  SAND  MOULDING     183 


it  is  necessary  to  fill  with  sand  all  the  area  not  occupied 

by  the  half  pattern,  for  the  temporary 

purpose  of  affording  a  perfectly  level 

bed  to  ram  on.    This  sand  is  strickled 

off  level  with  the  half  pattern  which 

has  just  been  rammed,  the  top  face  of 

the  pattern  affording  a  suitable  guide 

for  the  levelling.    Parting  sand  may 

be  strewn  over  the  face  so  obtained ; 

but  it  is  better  to  lay  sheets  of  brown 

paper  over  a  large  surface   of  sand 

which  has  to  be  rammed  on,  because 

it  does  not  yield  so  readily  as  the  sand 

beneath  the  rammer,  and  the  surface 

therefore  comes  out  more  free  from 

inequalities.    The  cope  is  well  liftered, 

and  vented  over  the  areas  occupied  by  the  cross.    After 

it   is  taken   off,  and  turned   over,  the  surface   of  the 


FIG.  107.— BOARD 

FOR  STRIKING 
CENTRAL  CORE. 


FIG.  108. — VERTICAL  SECTION  THROUGH  COMPLETED  MOULD. 

sand  is  tried  with  the  fingers,  and  portions  that  happen 
to  be  too  loosely  rammed  are  consolidated,  and  the  sur- 
face is  properly  smoothed,  finished,  and  blackened. 


184  PRACTICAL  IRON  FOUNDING 

The  other  half  of  the  mould  is  now  made.  The  half 
pattern  is  withdrawn  from  the  portion  just  rammed  and 
turned  around  into  its  new  position,  the  temporary  sand 
on  which  the  cope  was  rammed  being  mostly  dug  away 
and  removed  to  receive  the  half  pattern,  which  is  set  by 
the  same  methods  as  before.  The  joint  face  across  the 
centre  is  set  over  the  centre  of  the  mould  of  the  boss, 
and  the  top  face  of  the  plate  is  levelled  in  all  directions. 
At  the  locality  where  the  ribs  come  against  the  ribs  already 
moulded,  the  moulded  portion  is  filled  in  with  pieces  of 
wood  to  prevent  the  sand  from  being  pushed  into  the 
mould.  After  this  is  done,  the  ramming,  venting,  and 
rodding  proceed  precisely  as  the  same  operations  were 
performed  on  the  first  half  of  the  mould.  Fig.  106  shows 
the  mould  as  it  appears  at  this  stage,  one-half  being 
finished,  and  the  half  pattern  lying  rammed  in  the  other 
portion. 

The  central  core  is  struck  against  the  board,  Fig.  107, 
with  a  core  bar,  hay  bands  and  loam.  The  core  is  stood 
in  the  bottom  print  in  the  pin  mould,  it  enters  the  top 
print  in  the  cope,  and  the  core  bar  projects  through  the 
cope  to  bring  off  the  vent  from  the  core.  The  mould  is 
poured  at  the  central  boss,  and  one  riser  or  flow- off  gate 
is  brought  up  from  the  end  of  each  arm.  The  mould,  as 
thus  completed,  is  shown  in  Fig.  108. 


CHAPTER  X 

DRY  SAND  MOULDING 

WHETHER  the  metal  is  poured  into  green  sand  or  dry  sand 
does  not  affect  the  essential  methods  of  moulding  adopted, 
since  the  same  processes  of  turning  over,  liftering,  rod- 
ding,  and  sprigging  are  employed  in  each  case.  But  the 
classes  of  work  done  by  each  method,  and  the  mixtures 
of  sand  used,  are  different.  Heavy  work,  and  that  which 
is  wanted  specially  sound  and  free  from  blow-holes,  is 
cast  in  dry  moulds.  Strong  mixtures  of  sand  alone  can 
be  dried. 

A  dried  sand  mould  must  be  dry.  This  may  seem  a 
needless  truism,  but  the  point  is  one  of  very  great  im- 
portance. Since  the  mould  depends  for  its  venting  on  its 
porosity,  the  presence  of  moisture  even  in  small  quantity 
implies  that  the  vents  are  impeded. 

If  green  sand  mixtures  were  dried  in  the  stove,  they 
would  pulverize  and  fall  to  pieces.  And  the  strong  mix- 
tures also  which  are  used  for  dried  moulds,  though  hard 
and  sufficiently  firm  to  resist  great  pressure  of  metal,  are 
very  tender  when  edges  are  concerned.  For  this  reason 
the  joint  edges  of  such  moulds  are  always  finned,  that  is, 
their  immediate  faces  are  pressed  down  with  the  trowel 
while  the  mould  is  yet  green,  so  that  when  the  joints 
are  brought  together  the  edges  remain  slightly  asunder, 
as  in  Fig.  109,  A .  A  fin  or  thin  film  of  metal  of  course  forms 
here,  but  this  is  of  no  consequence;  while,  on  the  other 

185 


186  PRACTICAL  IEON  FOUNDING 

hand,  a  crushed  joint  edge  with  the  consequent  falling 
of  the  sand  into  the  mould  would,  if  extensive,  result  in 
a  waster  casting. 

Another  point  to  be  noted  in  connection  with  dried 
sand  moulds  is,  that  they  will  bear  harder  ramming  than 
those  in  green  sand,  since  they  become  porous  in  drying. 
For  the    same   reason,    less  venting  with  the   wire   is 
required.     The  very  close  nature  of  the  sand  demands 
that  its  venting  be  perfect,  and  it  can  only  be  properly 
vented  by  the  drying  out  of  the  moisture,  and  the  car- 
bonization and  desiccation   of    the  hay  in  the    horse- 
manure.   As  long  as  steam,  even  in  small 
quantity,  is  seen  coming  from  the  mould, 
pouring  is  unsafe,  and  the  mould  should 
properly  be  returned  to  the  stove.    But 
a   steaming  mould   poured  while  warm, 
that   is,    soon    after    removal    from    the 
FIG.  109.        stove,   is  less   risky  than    one  which    is 
FINNED  JOINT,   allowed  to   become    cold  first.    There  is 
also   this  advantage   in   the  use  of  dry 
sand,  that  less  gas  is  generated  than  in  moulds  made 
in  green  sand.    This  is  a  consideration  in  large  moulds 
involving  a  great  deal  of  work,  because  the  presence  of 
gas  in  quantity  is  apt  to  cause  blow-holes  and  scabs, 
and  any  arrangement  by  which  its  amount  can  be  re- 
duced is  a  distinct  advantage. 

Dried  sand  moulds  will  also  bear  more  swabbing  than 
those  made  in  green  sand.  Too  much  moisture  in  green 
sand  is  always  a  source  of  danger.  But  the  swab  may  be 
used  freely  in  dry  sand,  and  this  is  often  advantageous 
at  the  time  of  withdrawal  of  the  pattern  or  of  mend- 
ing up,  and  the  heat  of  the  drying  stove  removes  the 
moisture. 


DRY  SAND  MOULDING  187 

As  in  green  sand  moulding,  so  in  dry,  stronger  facing 
mixtures  are  used  in  the  vicinity  of  the  pattern  than  in 
the  body  of  the  mould.  The  floor  sand,  either  alone  or 
mixed  with  slight  proportions  of  stronger  sand,  is  used 
for  mere  box  filling.  The  cost  of  dry  sand  moulding  is  in 
excess  of  that  done  in  green  sand  because  of  the  extra 
cost  of  coke  for  drying.  But  this  depends  partly  upon 
the  system  of  the  shop.  When  drying  is  extensively  em- 
ployed the  percentage  of  expense  is  comparatively  small, 
especially  when  the  superiority  of  the  castings  and  the 
lower  ratio  of  wasters  are  taken  into  account. 

Moulding  Cylinders. — In  this  work  two  cardinal  mat- 
ters are  the  durability  of  wearing  surfaces,  and  the 
elimination  of  injurious  shrinkage  strains.  The  first  is 
got  by  the  employment  of  a  liner  of  harder  metal  than 
that  which  is  used  in  the  cylinder  body:  the  second  by 
avoiding  much  excess  of  metal  in  any  one  locality.  Neg- 
lect of  the  first  results  in  excessive  and  rapid  wear  of  the 
bore,  due  to  the  friction  of  the  piston  and  the  hot  steam ; 
neglect  of  the  second  results  in  blow-holes,  internal 
strains  and  possibly  fracture.  The  simpler  a  casting  can 
be  made  the  better  for  the  moulder,  who  cannot  ensure  a 
sound  casting  if  big  masses  of  metal  are  lumped  in 
proximity  to  thin  parts.  And  if  the  latter  are  those  which 
have  to  be  tooled,  the  most  careful  feeding  from  head 
metal  will  not  ensure  clean,  sound  surfaces. 

In  carrying  out  the  work  of  cylinder  making,  two  im- 
portant details  have  to  be  considered.  One  is  the  ques- 
tion either  of  using  a  pattern,  or  of  striking  up  the  mould 
in  loam;  the  other  is  whether  to  cast  horizontally,  or  on 
end.  Neither  admits  of  an  absolute  decision,  but  must 
be  settled  by  special  conditions.  In  brief,  the  choice  of 
the  first  method  in  work  of  medium  size  is  generally  de- 


188  PRACTICAL  IRON  FOUNDING 

termined  less  by  dimensions  than  by  numbers  required 
off.  For  small  castings,  however,  a  pattern  would  almost 
invariably  be  made,  even  though  one  or  two  castings 
only  should  be  required.  Some  saving  even  then  might 
be  effected  by  striking  up  the  pattern  body  in  loam,  in- 
stead of  building  it  in  timber  lagging,  and  then  fitting 
the  valve  casings,  flanges,  etc.,  in  wood,  to  the  loam,  and 
moulding  then  from  that  composite  pattern,  in  green  or 
in  dry  sand,  exactly  as  in  the  case  of  a  full  timber 
pattern.  In  the  largest  work,  loam  moulding  is  invari- 
ably adopted.  That  is,  the  mould  is  swept  round  against 
its  brick  backings,  and  the  valve  seatings  and  small  at- 
tachments are  made  as  pattern  parts  in  timber,  to  be 
embedded  in  the  loam  by  measurement. 

The  question  of  casting  horizontally  or  vertically 
seldom  arises  except  in  the  case  of  the  smaller  cylinders, 
which  are  moulded  from  full  patterns.  A  goodly  number 
of  firms  make  their  cylinders  horizontally,  and  with 
satisfactory  results.  Many  men  think  the  vertical  pour- 
ing, with  head  metal,  the  safer,  and  would  prefer  that  to 
the  other;  although  admitting  that  by  using  clean  hot 
metal,  and  by  extended  experience,  excellent  results  are 
obtained  in  the  other  way  in  shops  which  deal  with 
cylinder  work  in  large  quantities.  And,  after  all,  the  cost 
of  turning  moulds  up  on  end  and  fixing  cups,  etc.,  for 
vertical  pouring,  does  not  amount  to  much,  and  it  gets 
rid  of  all  risk  of  open  metal  on  the  upper  portion  of  the 
cylinder  bore.  Certainly  it  is  much  the  safer  plan  in  the 
average  class  of  shop. 

The  annexed  figures  represent  a  double  cylinder  made 
in  dry  sand,  cast  with  circular  guides  for  the  crosshead, 
having  a  foot  for  bolting  to  a  convenient  base,  and  with 
steam-chests,  all  in  one.  It  is  a  good  example  of  rather 


190  PRACTICAL  IRON  FOUNDING 

elaborate  coring-out.  Figs.  110  to  113  show  views  of  the 
casting.  Fig.  110,  right  hand,  gives  a  plan  view  of  the 
cylinder  and  guide,  and  a  section  through  the  same. 
Fig.  Ill  is  a  half  cross  section  through  the  cylinders  on 
the  line  A-B — that  is,  through  the  exhaust  passages, 
and  a  half  cross  section  through  the  cylinders  on  the 
line  C-D — that  is,  through  the  steam  inlet  passages. 
Fig.  112  is  a  longitudinal  elevation;  Fig.  113  a  half 
section  through  the  guides  on  the  line  E-F  in  Fig.  110 ;  G, 
Fig.  110  is  the  steampipe  in  plan;  H,  the  exhaust  ditto. 
We  see  at  a  glance  that  this  can  only  properly  mould 
in  one  way — and  that  is  as  in  the  plan  view  Fig.  110.  There 
are  several  troublesome  features  about  that  method  of 
moulding,  but  not  nearly  so  many  as  there  would  be 
with  any  other  method.  We  settle  instinctively  that  it 
must  part  along  the  line  I-J,  Figs,  112  and  118;  and  a 
glance  now  at  the  lifts  shows  us  that  several  coreboxes  are 
absolutely  essential.  Thus,  I-J  representing  the  joint  alike 
of  the  pattern  and  mould,  the  overhanging  parts  at  K 
will  not  lift;  hence  they  must  be  cored,  or  the  overhang 
must  be  formed  with  loose  strips,  which  in  this  case,  at 
least,  are  not  desirable.  Then  (see  Figs.  110  and  111)  the 
steamchests  must  evidently  be  cored,  and  their  cores 
must  carry  those  also  for  the  various  passages.  The 
hollow  space  M  beneath  the  foot  in  Fig.  113  would  deliver 
very  well,  but  cutting  it  out  in  the  pattern  would  involve 
considerable  trouble,  and  be  rather  weakening  to  the 
pattern  itself,  while  it  offers  every  facility  for  simple 
coring.  So,  not  of  necessity,  but  for  convenience,  we 
core  that  out.  The  cylinder  bores  and  the  guides  are 
necessarily  cored.  The  space  N,  Fig.  Ill,  between  the 
pattern  joint,  and  under  the  passages  G  to  II,  must  also 
be  cored.  There  is  a  space  0,  Fig.  113,  which  reaches  from 


DRY  SAND  MOULDING 


191 


r 


n 


D 


D 


the  pattern  and  mould  joint  to  the  plate  or  web  which 
connects  the  two  crosshead  guides,  and  this  also  must  be 
cored.    Being  cast  on  end, 
the  necessary  head   metal 
will  be  put  at  P,  P.    These 
considerations     settle    the 
essential  methods  of   con- 
struction. 

To  mould  the  cylinder, 
the  half  containing  the 
steam  and  exhaust  pass- 
ages is  first  rammed  up  in 
a  mixture  of  dry  sand,  the 
joint  face  being  laid  on  a 
joint  board,  and  the  drag 
or  top  part  placed  around 
the  pattern.  There  is  no- 
thing about  the  ramming 
of  this  that  calls  for  any 
special  comment.  The  sand 
is  rammed  hard  in  detail 
and  vented,  all  its  weak 
corners  and  angles  are  well 
strengthened  with  nails  and 
rods,  and  the  mass  of  over- 
lying sand  is  properly  lif- 
tered.  Then  the  drag  is 
turned  over,  the  other  half 
pattern  laid  on,  and  the  top  H 

rammed,  the  flasks  parted, 

the  mould  cleaned,  the  joints  tinned,  and  the  boxes  run 
into  the  stove  to  dry.  But  the  real  work — that  which 
presents  difficulty,  or  at  least  that  which  demands 


CO 


192  PRACTICAL  IRON  FOUNDING 

especial  care — has  yet  to  be  done,  and  this  will  now  be 
illustrated  in  detail  : 

The  two  great  requisites  in  cylinder  work,  after  the 
usual  and  ordinary  precautions  common  to  all  moulds, 
are  the  proper  venting  of  the  cores,  the  proper  securing 
of  the  same,  .and  the  making  of  safe  and  sufficient 
provision  for  carrying  off  the  air  away  from  the  mould. 
The  making  of  the  cores  is  accomplished  precisely  on  the 
same  lines  as  any  ordinary  dried  cores,  but  since  some 
of  them  are  flimsy,  rather  more  caution  has  to  be  exer- 
cised in  their  case.  Taking  the  port  cores  first,  there 
are  two  usual  modes  of  venting — one  with  rods,  the 
other  with  strings, — each  of  which  is  practised  indiffer- 
ently, the  latter  being  most  suitable  for  the  smallest  cores 
of  all.  For  the  smallest  curved  passage  cores,  fine  string- 
soaked  in  tallow  may  be  used,  and  when  the  cores  are 
dried,  the  tallow  melting  away,  leaves  the  string  slack. 
When  strings  are  used  for  cores  of  moderate  size  they 
are  either  drawn  out  while  the  core  is  green,  or  after  it 
has  been  dried.  When  drawn  out  while  green  there  is  a 
tendency  of  the  string  to  cut  through  the  cores  at  the 
corners.  But  if  rods  are  rammed  up  crosswise,  as  shown 
at  a,  a,  Fig.  114,  which  illustrates  a  section  along  a  core 
in  the  plane  of  one  of  the  strings,  the  strings  can  be 
pulled  out  without  much  risk.  When  the  strings  are 
greased  and  allowed  to  dry  in  the  stove,  their  charred 
fragments  can  usually  be  blown  out  of  the  dried  core 
with  the  bellows.  The  extreme  end  of  the  vent  at  A  is 
filled  up  with  sand  to  prevent  the  entry  of  the  metal — all 
the  air  being  brought  away  at  the  opposite  end  of  the 
core,  coming  off,  therefore,  into  the  print  impressions. 

When  rods  are  used,  there  are  corresponding  numbers 
of  holes  bored  in  the  corebox,  as  shown  in  Fig.  115,  and 


PLATE  VII 


Seep.  2so 

192.— THE  DARLING  AND  SELLERS  LIGHT  MACHINE 


.  288 


[Facing  p. 


FlG.  193.  _  WOOLNOUGH  AND  DELMER  MACHINE 


DRY  SAND  MOULDING 


193 


these  rods  are  thrust  through  the  holes  into  the  box,  and 
the  core  is  rammed  around  them,  taking  care  to  keep 
them  central  with  the  thickness.  If  they  get  much  out 


FIG.  114. 


FIG.  115. 


FIG.  116. 


FIG.  117. 


FIG.  118. 

PASSAGE  CORES. 

of  centre  there  is  a  danger  of  the  metal  bursting  into 
the  vents,  and  causing  a  blown  casting.  The  figure 
shows  the  corebox  with  the  rods  in  situ,  in  readiness  for 
ramming.  After  the  core  is  dried,  at  the  corners  oppo- 
site each  rod,  Fig.  116,  a,  a,  a  narrow  groove  is  filed, 

o 


194  PRACTICAL  IRON  FOUNDING 

going  down  to  meet  the  terminations  of  the  holes  formed 
by  the  rods.  A  string  is  inserted  a  little  way  into  one 
hole,  and  carried  round  the  curve,  and  through  the 
other  hole  at  right  angles  with  the  first.  Now  the  por- 
tion filed  out  is  filled  up  again  round  the  inserted  string 
with  core  sand,  and  the  string  drawn  out,  thus  leaving 
a  clear  passage  round  the  curve.  The  continuity  of  the 
vents  should  always  be  tried  with  the  bellows  for  security. 
In  the  smaller  cores  it  is  not  usual  to  carry  the  vents 
right  round — the  air  striking  away  readily  from  the 
short  unvented  portion.  The  extreme  end  of  the  vent  is 
of  course  always  filled  up  with  a  plug  of  sand. 

In  addition  to  the  rods  for  venting,  a  rod  or  rods  have 
to  be  rammed  in  to  stiffen  the  core  and  to  furnish  the 
means  of  its  attachment  or  anchoring,  a  hook  being 
formed  on  the  core  rod  or  rods  for  the  purpose,  as  shown 
in  Fig.  117,  which  illustrates  a  core  cut  through  in  the 
plane  of  a  core  iron. 

The  steam  and  exhaust  cores  are  made  somewhat 
differently.  The  corebox  parts  in  two,  one-half  of  the 
exhaust  box  being  shown  in  plan,  etc.,  in  Fig.  118.  Each 
half  is  rammed  up  separately,  and  the  two  stuck  to- 
gether. The  shape  of  the  stiffening  wires  is  seen  in  plan, 
in  fall  lines  on  the  right-hand  side,  the  core  being  sup- 
posed to  be  only  partially  rammed  up  there.  The  vent  is 
cut  out  with  the  trowel  in  the  joint,  as  shown  in  the 
left-hand  side,  which  illustrates  the  half-core  finished; 
so  that  when  the  halves  are  cemented  together,  a  central, 
rudely  circular  vent  traverses  the  whole  length  of  the 
core.  The  appearances  of  the  ends  of  the  complete  core 
when  cemented  are  shown  in  side  and  end  views. 

The  steam-chests  are  cast  with  the  cylinders,  the 
covers  then  being  plain  plates.  Hence  the  prints  for  the 


DRY  SAND  MOULDING 


195 


port,  and  exhaust  cores,  are  placed  in  the  steam-chest 
corebox.  Also,  since  it  is  an  advantage  to  be  able  to  drop 
the  port  cores  down  from  the  top  rather  than  to  thrust 
them  into  their  prints  horizontally,  the  prints  are  con- 
tinued up  to  the  top,  a,  Fig.  119,  and  the  cores  stopped 
over  when  finally  in  place. 

Fig.  120  shows  the  core  finished.  The  central  portion 
is  filled  with  ashes,  and  a  few  rods  are  placed  about  to 
stiffen  the  body.  Since  the  exact  distance  between  the 
port  and  exhaust  cores  where  they  pass  out  at  the  valve 
facing  is  important  as  affecting  cut-off,  TV  in.  is  allowed 


FIG.  119.  FIG.  120. 

STEAM  CHEST  Box  AND  CORE. 

for  machining  along  their  edges.  Hence  the  reason  of 
the  shoulders  in  the  cores,  Figs.  114  and  117,  which  are 
the  reduced  widths,  giving  the  tooling  allowance.  Further, 
to  avoid  broken  print  edges  and  mending  up,  careful 
moulders  often  ram  up  strips  of  hoop  iron  against  the 
sides  of  the  prints,  a,  a,  a,  Fig.  120,  which,  when  em- 
bedded in  and  forming  a  portion  of  the  core,  are  an 
absolute  and  secure  guide.  An  eye,  or  a  couple  of  eyes, 
are  rammed  in  the  core  for  lifting  it  into  place,  and  an 
eye  projects  from  the  back  for  securing  it  bodily  against 
the  side  of  the  flask. 

The  main  core  E  in  Fig.  110  may  be  made  either  in 
a  box  or  from  a  board.    If  several  castings  have  to  be 


196 


PRACTICAL  IRON  FOUNDING 


made — say  over  three  or  four — a  box  pays  for  its  first 
cost;  if  only  one  or  two  castings,  then  a  board  is  cheaper. 
If  a  board  is  used,  as  in  Fig.  121,  it  is  evident  that  the 
cored-out  openings  in  the  sides  of  the  guides  (see  Fig.  113) 
cannot  be  struck,  but  must  be  made  with  a  corebox. 
The  section  of  this  box  will  then  be  that  shown  in  Fig. 
122;  and  the  cores  may  then  be  made  separately  from  the 


FIG.  121. — STRIKING  BOARD. 


main  core,  being  rammed  on  a  bedding  of  sand  struck  to 
the  contour  of  the  box;  or  else  on  a  bottom  board,  and 
nailed  to  the  main  core  after  they  are  dried.  Or,  they 
can  be  rammed  directly  on  the  main  core,  as  in  Fig.  123, 


FIG.  122. 


FIG.  123. 


GUIDE  CORES. 


after  the  main  core  has  been  wholly  or  partially  dried, 
the  surface  being  cut  up  a  little  with  the  trowel  and 
moistened  with  clay  water,  and  nails  stuck  in  at  intervals 
to  assist  adhesion. 

The  section  of  the  main  core  is  shown  at  Fig.  123,  a 
small  bar  being  used  to  go  through  the  narrow  neck 
which  carries  the  bush.  This  bar  cannot  be  large,  but 
must  be  as  large  as  convenient.  Thus,  if  the  neck  were 


DRY  SAND  MOULDING 


197 


cored  to  2  in.  diameter,  the  bar  might  be  If  in.  to 
allow  just  a  thin  layer  of  tow  between  the  bar  and  the 
loam.  But  the  portions  which  form  the  cylinders  and 
the  guides  being  much  larger,  the  If  in.  bar  must  either 
be  wedged  into  two  larger  bars — one  at  each  end — or  the 
increased  size  must  be  covered  with  core  plates  and  hay 
bands.  The  first  plan  is  not  desirable  in  this  case,  through 
lack  of  rigidity,  so  the  second  is  to  be  preferred.  The 
section  of  this  core,  then  struck  on  such  a  small  bar,  and 
taken  through  a  layer  of  hay  bands,  is  that  represented 
in  Fig.  123. 

When  a  corebox  is  used,  a  half-box  will  suffice,  by 


A 

FIG.  124  FIG.  125. 

HALF  Box  AND  CORE. 

making  two  half-cores,  and  cementing  them  together. 
Each  half  is  stiffened  with  rods,  and  a  vent  passage  is 
cut  through  the  joint.  Fig.  124  shows  a  section  through 
the  half-corebox,  taken  through  the  centre  of  one  of  the 
guides,  and  Fig.  125  is  a  section  through  the  finished  core 
in  the  same  position,  A  being  the  rods.  These,  of  course, 
are  not  straight,  since  they  have  to  pass  through  the 
narrow  neck,  but  are  bent  beyond  the  neck  to  occupy  the 
positions  in  the  large  diameter  shown  at  A. 

The  remaining  cores  call  for  no  comment,  their  con- 
struction being  quite  apparent  from  the  figures. 

We  now  suppose  that  the  mould  is  completed,  dried, 
and  ready  for  coring  up.  Before  the  cores  are  blackened, 


198 


PRACTICAL  IRON  FOUNDING 


they  are  all  tried  in  place  to  see  that  they  fit  properly 
and  leave  the  proper  amount  of  metal  everywhere.  Then 


o 


FIG.  126. — MOULD  COKED  UP. 

they  are  blackened,  put  back  in  the  stove  for  a  few  hours, 
or  for  a  night,  and  are  ready  to  go  finally  into  place. 
Even  more  care  has  to  be  exercised  in  this  particular  with 
cylinders  than  with  work  of  ordinary  character,  when 


DRY  SAND  MOULDING 


199 


the  cylinders  are  not  cast  in  the  position  in  which  they 
are  cored,  but  vertically,  when  any  insecure  fixing  will 
make  itself  manifest,  to  the  great  grief  of  the  luckless 
moulder  when  he  comes  to  his  work  on  the  following 
morning. 

In  the  first  place,  then,  that  portion  which  was  first 


FIG.  128. 
MOULD  CORED  UP. 

rammed,  the  bottom  part — though  actually  the  cylinders 
are  cast  vertically, — is  laid  on  blocking  or  any  convenient 
support,  joint  face  upwards.  Then  the  steam-chest  cores 
are  laid  in  their  print  impressions — see  Fig.  126  (A,  A), 
which  gives  a  plan  view  of  the  mould,  representing  it  as 
it  appears  at  certain  stages  of  the  work;  and  Figs.  127  and 
128  (A,  A),  which  are  sectional  views  across  the  mould 


200  PRACTICAL  IRON  FOUNDING 

through  the  centre  of  the  steam  passage  cores  F,  and  ex- 
haust cores  G,  respectively. 

The  vents  from  the  cores  A,  A  are  brought  away 
through  holes  B  in  the  sides  of  the  box  part;  a  channel 
also,  shown  in  Fig.  128,  being  cut  in  the  sand  from  these 
holes  to  the  back  of  the  cores,  which  cores  may  be 
fastened  with  or  without  screw  bolts.  If  they  were 
heavy,  and  their  overhang  very  considerable,  they 
should  properly  have  been  attached  with  a  screw  bolt, 
passing  from  an  eye  in  the  core  through  a  hole  in  the 
box  side,  as  shown  at  0,  Fig.  126.  But  in  this  instance 
the  core  is  well  supported  in  its  print  impression,  and 
is  not  of  very  large  size.  Hence  a  little  dodge,  such  as 
that  shown  at  D,  D,  Fig.  126  is  sufficient  to  hold  the  core. 
A  shallow  groove  is  filed  on  each  side  of  it,  vertically, 
and  grooves  in  the  mould  sides  in  corresponding  posi- 
tions; and  while  the  core  is  held  back,  bedding  against 
its  print,  this  is  filled  up  with  damp  core  sand,  which, 
when  dried,  becomes  an  interlocking  key  or  dovetail, 
holding  the  core  securely  in  place.  Another  simple  way 
is  that  shown  at  Figs.  126  and  128  at  E,  where  a  loop  of 
wire  is  slipped  through  the  eye  of  the  core,  and  carried 
out  through  a  channel  cut  for  it  in  the  sand,  and  a  short 
bit  of  rod  is  pushed  through  the  loop  and  down  into  the 
body  of  sand,  thus  holding  the  core  securely  back  in 
place. 

Afterwards,  the  steam  and  exhaust  cores  F  and  6r, 
which  (Figs.  126-128)  connect  their  pipes  with  the  two 
steam-chests,  are  placed  in.  These,  when  laid  in,  have  to 
fit  their  bottom  print  impressions,  and  also  the  impres- 
sions in  the  steam-chest  cores,  and  to  allow  the  correct 
thicknesses  in  bottom  H  and  sides  /;  which  thicknesses 
will  have  been  tested  at  the  first  trying-in  of  the  cores, 


DRY  SAND  MOULDING  201 

both  by  measurement  and  by  the  use  of  clay  thickness 
pieces  in  the  bottom  where  direct  measurement  is  riot 
available.  The  vents  from  these  cores  are  not  brought 
into  the  steam-chest  cores  at  all,  but  through  the  round 
prints  J  in  Figs.  127  and  128.  There  is  a  difference  in  the 
way  of  fitting  these  to  the  steam-chest  cores.  The  exhaust 
core,  Figs.  126  and  128,  Gr,  fits  the  steam-chest  through 
nearly  the  whole  depth  of  the  latter.  But  this  is  not  the 
case  in  the  steam-passage  core,  Figs.  126  and  127,  F; 
for  it  enters  the  chest  at  one  corner,  the  bottom  corner 
as  the  mould  lies  (see  Fig.  127),  K.  Hence  it  is  necessary 
to  make  provision  for  its  support.  To  trust  to  chaplet 
nails  only  when  the  mould  has  to  be  up-ended  for  casting 
is  not  safe.  A  ledge  therefore  is  formed  on  core  A ,  as 
shown  at  K,  on  which  the  steam-passage  core  rests.  This 
may  then  be  either  stopped  over  with  a  small  rectangular 
core  L,  as  in  Fig.  127— left-hand — nailed  on ;  or  the  box 
may  be  so  formed  as  to  continue  core  F  to  the  top,  and  so 
stop  itself  off,  as  shown  at  M,  on  the  right-hand  side  of 
the  same  figure.  In  either  case  the  result  is  the  same — 
the  leaving  a  steam  entry  of  width  N  into  the  steam-chest. 

Each  core  is  secured  in  its  bottom  print  by  means  of 
a  wire  carried  from  it  through  the  box,  and  twisted  fast 
round  a  bit  of  iron  rod,  Figs.  127  and  128,  O,  O. 

There  is  now  the  core  which  forms  the  inter-cylinder 
space,  seen  at  N  in  the  drawing  of  the  actual  casting, 
Fig.  111.  This  might  deliver  itself  as  part  of  the  mould  by 
leaving  the  portions  of  the  steam  and  exhaust  pipes  which 
bridge  across  it,  G  and  H,  in  Figs.  110  and  111  loose.  It  is 
better,  however,  to  core  it,  and  this  is  shown  in  Figs.  127 
and  128.  The  core  P,  therefore,  is  shown  fitting  in  its 
print  impression  Pl  in  both  views  (Figs.  127  and  128), 
the  print  thickness  Pl  happening  to  coincide  with  the 


202  PRACTICAL  IRON  FOUNDING 

thickness  of  the  metal  in  the  steam  and  exhaust  pipes. 
This  shouldering  of  the  print  takes  place  beyond  the 
pipes,  hence  the  appearance  of  the  core  in  Figs.  127  and 
128.  The  vent  from  this  core  is  carried  out  at  the  back, 
in  a  line  with  O,  and  beyond  it,  of  course,  in  the  figures. 
The  main  cores  Q,  Figs.  126  and  128,  are  next  placed  in 
their  print  impressions,  one  only  being  shown  in  Fig.  126 
to  the  right.  The  precautions  to  be  observed  here  are  to 
see  that  the  cores  do  not  sag  in  consequence  of  the  narrow- 
ing of  the  diameter  at  the  neck  which  forms  the  stuffing 
box,  and  that  the  thicknesses  of  metal  are  equal  all 
round,  the  equal  thicknesses  being  dependent  first  on 
the  truth  of  the  cores,  and  second  on  the  concentricity 
of  the  prints  with  the  pattern  cylinders.  Clay  thickness 
pieces  will  be  placed  underneath  the  cores  for  this  pur- 
pose, and  measurement  will  be  also  taken  at  the  sides. 
When  the  thicknesses  are  obtained,  chaplets  will  be 
driven  in  to  sustain  the  weight  of  the  cores  about  the 
central  portions,  avoiding  those  parts  which  have  to  be 
bored.  The  proper  position  for  the  chaplet  in  this  case  is 
at  Q\  Fig.  126,  under  the  shouldered  or  stepped  portion 
lying  between  the  cylinder  bore  and  the  guide. 

Again,  when  ramming  up  cylinders  the  vents  of  which 
have  to  be  brought  away  at  the  ends  in  the  fashion  to  be 
noted  immediately,  it  is  necessary  to  cut  away  the  sand  in 
continuation  of  the  print  beyond  the  front  end — that  is, 
the  space  enclosed  between  the  dotted  lines  R  in  Fig.  126 
— which  sand  is  made  good  after  the  cores  are  finally  set 
in  place.  Since  the  mould  has  to  be  up-ended  for  casting, 
there  is  just  the  slightest  chance  of  the  cores  shifting 
downwards  slightly,  and  a  careful  moulder  will  leave 
nothing  to  chance.  Hence  at  this  stage  it  is  desirable  to 
ram  up  two  rods,  or  pieces  of  flat  or  round  iron,  against 


DRY  SAND  MOULDING 


203 


the  core  end,  cutting  away  and  letting  it  go  down  a  little 
into  the  body  of  hard  sand  below,  as  shown  at  Fig.  126  in 
the  space  R.  Or,  if  there  is  sufficient  room  above  the 
vent,  a  small  flat,  square  piece  can  be  rammed  in,  and 
kept  in  place  with  a  rod  bearing  at  the  other  end  against 
the  inside  of  the  flask,  as  shown  at  S.  The  holes  Ql  l  in 
the  centre  of  the  cores,  in  Figs.  127  and  128,  are  the  vents 
through  which  the  air  strikes  away  from  these  cores,  and 
they  pass  completely  through  from  end  to  end. 

If  the  box  is  specially  con- 
structed for  moulding  cylin- 
ders of  one  particular  size, 
it  will  be  made  with  holes 
in  its  joint  face  opposite  the 
air  channels  in  the  main 
cores,  as  shown  at  Hl,  H\ 
Fig.  126;  and  the  air  will 
then  be  taken  directly  away. 
But  in  cases  where  ordinary 
flasks  are  used,  the  air  is 
readily  taken  off  at  the  back, 
between  the  bars,  in  the 
manner  shown  in  Fig.  129, 

which  gives  a  part  section  through  the  corner  of  the  box. 
Here  A  is  a  diagonal  passage  cut  in  the  end  of  the  core  B, 
establishing  a  communication  between  the  main  channel 
in  the  core,  and  the  vent  passage  to  be  formed  between 
the  bars,  the  sand  passage  being  made  by  ramming  up  a 
piece  of  rope  C  in  the  end  of  the  mould,  from  which  the 
sand  has  been  removed,  as  just  now  noted,  thrusting 
first  one  end  a  little  distance  into  the  core  vent,  and 
bringing  the  free  end  outside  the  flask,  as  shown.  After 
the  sand  has  been  rammed,  the  rope  is  drawn  out, 


FIG.  129.— VENT  EOPE. 


204  PRACTICAL  IRON  FOUNDING 

leaving  a  free  communication  between  the  core  and  the 
outside.  The  newly-made  sand  is  shown  darker  than 
the  rest  in  the  figure,  and  this  is  dried  now  with  a 
piece  of  red-hot  iron. 

The  difference  in  the  core  sections  Q  in  Figs.  127  and 
128  is  given  to  show  the  different  appearance  which  the 
cores  would  have  in  section  if  made  in  the  two  ways 
previously  described.  Fig.  128  illustrates  the  cores  as 
rammed  in  a  box,  with  the  four  stiffening  irons  in 
section.  In  Fig.  127  two  sections  of  a  struck  up  core  are 
shown,  that  on  the  right  hand  being  against  the  face  of 
a  coreplate,  that  on  the  left  through  the  haybands, 
which  come  intermediately  with  the  coreplates. 

Taking  the  port  cores  T,  T  in  the  figures,  one  fits 
against  the  cylinder  bore,  and  one  against  the  ring  which 
forms  the  recess  terminating  the  bore,  and  a  correspond- 
ing difference  for  the  lengths  is  made  in  the  corebox. 
Unless  the  cores  are  very  deep,  they  can  be  readily  put 
in  without  disturbing  either  the  steam-chest  or  the 
cylinder  core,  by  simply  sliding  them  round  the  body 
and  down  into  their  places.  If  they  are  very  deep,  as  in 
some  low-pressure  cylinders  of  compound  engines,  this 
cannot  be  done,  and  then  the  prints  in  the  steam- chest 
core  must  be  made  f  in.  or  J  in.  too  long,  to  allow  the 
passage  cores  to  pass  the  extra  space,  which  is  filled  up 
with  sand  after  they  are  in  position.  Fig.  130  shows  a  good 
plan  to  adopt  in  such  cases  as  these,  being  an  example 
taken  from  a  double-ported  compound  cylinder,  14  in. 
bore,  and  having  ports  9  in.  wide.  Each  single  port 
opening  being  narrow,  the  core  would  be  weak  and 
flimsy.  Hence  these  weak  sections  are  rendered  rigid  by 
connecting  them  together  at  the  otherwise  free  ends 
with  a  continuation  piece  of  core,  fitting  into  the  print, 


DRY  SAND  MOULDING 


205 


so  that  they  can  be  handled  without  risk  of  fracture. 
The  spaces  A,  A  are  necessary  in  order  to  be  able  to  get 
the  wide  port  cores  in,  and  they  are  filled  up  afterwards 
with  sand. 

The  vents  from  the  cores  T,  T  are  taken  off  into  the 
steam-chest  core,  no  vents  passing  into  the  cylinder  core 
at  all.  Sometimes,  though  seldom,  they  are  secured  into 
the  steam-chest  core.  But  the  chaplets,  Fig.  126,  U,  and 
the  claywash  daubed  around  the  print  joint,  and  the 
sand  by  which  they  are  stopped  over,  are  usually  quite 
sufficient  to  retain  them  in  place.  The  core  which  is 


FIG.  130. — STEAM  CHEST  AND 
PASSAGE  CORES. 


FIG.  131.— VENTS. 


uppermost  in  the  mould  is  grooved  on  the  face  which 
abuts  against  the  body  core,  in  order  to  allow  the  air  to 
pass  up  freely  at  the  time  of  casting,  Fig.  131. 

There  now  remain  the  cores  which  form  the  foot  of 
the  casting  underneath  the  guides.  These  are  three  in 
number,  and  are  shown  in  Fig.  132,  which  gives  a  plan  or 
face  view  of  the  opposite  half  of  the  mould  to  that  shown 
in  Fig.  126 ;  and  Fig.  133  is  a  sectional  view  of  the  same — 
showing,  however,  the  central  guide  cores  in  dotted  out- 
line, in  order  the  better  to  illustrate  the  relative  positions 
of  the  cores.  The  same  reference  letters  are  used  in  both 
figures,  but  the  guide  cores  are  entirely  omitted  from 


206  PRACTICAL  IRON  FOUNDING 

Fig.  132.  Each  of  these  cores  A,  A  is  well  guided  by  its 
print,  at  surfaces  on  the  outside,  end,  and  bottom;  and  B 
by  a  shallow  print  all  round.  They  are  all,  therefore, 
screwed  up  with  bolts  passing  through  holes  made 
temporarily  through  the  sand  between  the  bars,  to  the 
back  of  the  flask,  and  there  screwed  against  long  flat 
washer  plates  bridging  across  the  bars,  as  shown  in 
Fig.  133.  The  flask  is  turned  over  in  order  that  the  holes 
may  be  filled  in  with  sand,  rammed  around  the  bolts. 

The  cores  being  of  considerable  bulk,  have  cinders 
rammed  in  them  to  collect  the  air;  and  the  body  of  sand 
in  the  box  outside  of  the  cores  A,  A  is  also  vented  with 
cinders,  into  which  the  air  from  the  cores  is  conveniently 
brought,  and  out  through  holes  in  the  flask  sides,  or 
downwards  between  the  bars  to  the  back.  The  courses  of 
the  vents  are  indicated  by  the  dotted  lines  at  (7,  C,  C. 
Core  D,  though  shown  in  its  position  relatively  to  the 
dotted  cylinder  cores,  is  not  actually  fixed  in  this  half  of  the 
flask  at  all;  but  after  both  the  cylinder  cores  are  finally 
set  in  place  in  Fig.  126,  D  occupies  the  position  marked 
F,  V  in  that  figure  between  the  guides,  and  is  secured  in 
place  by  means  of  two  rods  shown  at  V,  V,  which  pass 
up  into  two  corresponding  holes  in  the  core  I),  Fig.  133,  of 
slightly  larger  diameter,  which  permits  of  sand  being 
rammed  around  to  lock  the  core  fast.  Chaplets,  shown 
at  E,  Fig.  133,  keep  the  cores  at  the  proper  distance  apart 
as  required  for  the  thickness  of  metal  in  the  foot. 

Very  few  chaplets  are  wanted  about  this  cylinder.  The 
outer  corners  of  the  port  cores  are  assisted  with  chaplets, 
and  the  thicknesses  of  metal  between  the  ports  themselves 
are  secured  by  two  spring  chaplets  or  by  double-headed 
ones.  Those  at  the  outer  corners  of  the  ports  have  their 
stalks  inserted  in  shallow  grooves  cut  in  the  sand  with  the 


DRY  SAND  MOULDING 


207 


trowel,  and  are  covered  up  and  fixed  with  moist  sand.  It 
would  often  be  desirable  to  secure  the  cores  still  further 


s 


O 


FIG.  132. 


FIG.  133. 
MOULD  CORED  UP. 


with  chaplets  abutting  against  the  base  of  the  cylinder, 
but  the  necessity  for  this  should,  when  practicable,  be 
prevented,  because  the  metal  becomes  chilled  round  a 


208  PRACTICAL  IRON  FOUNDING 

chaplet,  and  there  is  always  more  risk  of  a  blow  in  its 
vicinity  than  elsewhere.  In  all  places  where  cores  have 
been  stopped  over,  or  chaplet  stalks  inserted,  or  any 
mending-up  done,  the  damp  sand  must  be  dried  before  the 
closing  of  the  mould,  by  placing  red-hot  blocks  of  iron 
over  or  against  the  made-up  portions,  and  a  little  oil 
poured  over  and  around  them  will  lessen  the  generation 
of  gas. 

We  now  consider  what  provisions  have  to  be  made  for 
casting.  The  mould  has  to  be  poured  on  end — cylinders 
and  head  metal  uppermost.  The  runner  is  shown  in 

Fig.  126  at  W;  ingates  at 
X,  X,  two  or  three  of  the  latter 
to  each  cylinder,  dependent 
on  its  size.  A  plan  view  of  the 
runner  is  shown  in  Fig.  134, 
where  A  is  the  runner  and 

FIG.  134— INGATE  AND       B,B  are  the  ingates.     These 

EUNNEES.  are  cut  out  while  the  mould 

is  green.    At  C,  in  the  latter 

figure,  the  risers  are  shown,  through  which  feeding  takes 
place.  All  the  vents  are  examined  to  see  that  they  open 
out  clear;  the  fastenings  of  the  cores  are  all  made  sure 
of.  If  the  main  cores  have  been  made  in  a  box  and 
cemented  together  with  clay- wash,  there  is  just  a  fear 
lest  the  halves  should  slide  one  over-  the  other  on  up- 
ending, unless  they  fit  properly  in  the  ends  of  their 
prints.  It  is  scarcely  possible  to  exercise  too  much  care 
in  all  these  minutia3  before  finally  closing  and  up-ending 
the  mould,  because  should  anything  shift  it  cannot  be 
remedied  after  the  metal  is  poured  in. 

The  flasks,  well  cottered  or  screwed  together,  are  now 
lowered  into  a  pit  in  the  floor,  of  such  a  depth  as  to 


DRY  SAND  MOULDING  209 

bring  the  top  at  a  height  convenient  for  pouring.  A 
pouring  basin  and  risers  are  formed  in  the  usual  way. 
Vent  pipes  are  brought  up  from  the  cores  A,  B  in 
Fig.  138,  while  the  vents  from  the  body  cores  come  out  at 
C,  Fig.  129;  and  all  down  the  open  sides  the  vents  from 
the  mould  surfaces  come  out. 

Head-metal. — The  necessity  for  putting  head-metal  on 
castings  which  must,  when  machined,  have  perfectly 
clean  faces,  has  often  been  a  point  at  issue  between  the 
foreman  moulder  and  his  employer.  Generally,  a  moulder 
considers  head-metal  indispensable  in  engine  cylinders, 
hydraulic  cylinders,  and  rams,  while  the  employer  grudges 
the  cost  of  cutting  off  the  head,  and  maybe  thinks  that 
it  is  a  moulder's  fad,  especially  when  he  learns  that  there 
are  shops  in  which  cylinders  are  cast  without  heads. 

There  is  much  more  in  this  than  can  be  settled  off 
hand.  There  is  no  doubt  that,  under  some  conditions,  it 
is  safe  to  cast  without  heads;  but  these  conditions  do  not 
exist  in  jobbing-shops  doing  general  work,  and  mixing 
metal  at  random  for  all  the  work  of  the  day.  In  such 
shops,  when  it  is  desired  to  turn  out  good  sound  work, 
it  is  not  safe  to  cast  cylinders  without  head-metal,  and 
the  cost  of  sawing,  or  slotting,  or  turning  off  a  head 
is  but  a  trifle  compared  with  that  of  a  waster  casting.  In 
foundries  in  which  cylinders  are  a  speciality  it  is  often 
the  practice  to  dispense  with  heads;  by  mixing  special 
brands  of  metal,  pouring  it  hot  and  clean,  and  using  flow- 
off  gates  freely,  heads  are  not  found  requisite.  Often, 
then,  in  the  case  of  cylinders  moulded,  i.e.,  not  bricked 
up,  the  practice  is  to  mould  and  cast  them  horizontally 
instead  of  in  a  vertical  position. 

The  function  of  head-metal  is  essentially  two-fold:  It 
acts  as  a  receptacle  for  all  the  dirt,  scurf,  air  (which 

p 


210  PRACTICAL  IRON  FOUNDING 

would  otherwise  be  arrested  on  the  face  of  the  top  flange), 
and  it  also  becomes  a  feeder  to  supply  hot  metal  to  the 
shrinking  casting.  In  a  very  minor  degree  it  fulfils  a 
third  function — that  of  producing  liquid  pressure,  which 
tends  to  consolidate  the  metal  below;  but,  if  that  were 
all,  the  result  could  be  more  easily  secured  by  increasing 
the  height  of  the  pouring  basin  than  by  massing  a  rela- 
tively shallow  head  of  large  area  over  the  casting.  In- 
creasing the  depth  of  a  head  within  reasonable  limits 
increases  the  soundness  of  a  casting;  but  that  result 
follows  much  less  from  the  increased  hydrostatic  pressure 
than  it  does  from  the  function  of  the  head  as  a  feeder  of 
hot  metal.  The  latter  function  is  so  very  important  that 
it  is  usual  to  supplement  it  by  the  practice  of  mechanical 
feeding,  with  a  rod  through  the  runner,  see  p.  161,  and 
two  or  three  risers  besides. 

This  function,  therefore,  of  mechanical  feeding  is 
actually  the  most  important  one  which  the  head  has  to 
fulfil.  The  first-named,  that  of  collecting  dirt,  sullage, 
and  air  is  very  important  only  when  due  care  has  not 
been  taken  to  exclude  the  first  two  from  the  mould  alto- 
gether. Many  a  head  is  cut  off  with  scarcely  a  trace  of 
dirt  apparent,  or  an  air-hole  visible  in  it  when  broken  up 
for  remelting.  A  careful  moulder  and  furnaceman  will 
generally  keep  dirt  out  of  the  mould,  so  that,  if  this  were 
all,  the  top  flange  of  a  cylinder  would  face  up  clean  even 
though  no  head  metal  were  cast  on  it.  Hence  the  chief, 
and  almost  the  only,  function  of  head  which  is  worth 
consideration  is  that  of  a  feeder  to  the  casting.  It  is  to 
this,  therefore,  that  we  will  give  attention. 

It  is  well  known  that,  when  the  metal  in  adjacent 
parts  of  a  casting  is  very  disproportioned,  draws,  or  hollow 
and  open  spaces  will  occur  in  the  heart  of  the  heavier 


DRY  SAND  MOULDING  211 

metal,  see  p.  128.  This  is  caused  by  the  thinner  metal 
cooling  and  setting  before  the  heavier.  Since  the  latter 
continues  to  shrink  for  some  time  after  the  former  has 
congealed  it  becomes  drawn  away  from  the  central  parts, 
leaving  cavities  there;  the  nature  and  extent  of  these 
will  depend  on  the  relative  disproportion  of  the  masses 
and  on  the  character  of  the  metal  itself.  The  greater 
the  disproportion  present,  and  the  stiffer  and  stronger 
the  iron,  the  greater  will  be  the  extent  of  the  drawing. 
It  may  take  the  form  of  large  open  cavities,  or  it  may 
consist  of  very  coarse  open  crystallisation  with  minute 
rifts  between  small  masses  of  crystals,  or  it  may  partake 
of  both  characters — holes  and  coarse  crystallisation  and 
rifts  combined;  when  such  drawing  occurs  it  is  a  sure 
indication  that  there  is  disproportion  in  adjacent  masses 
of  metal.  Draws,  it  must  be  remembered,  are  not  to  be 
confounded  with  blow-holes  and  general  sponginess; 
which  occur  in  castings  regularly  proportioned.  Blow- 
holes are  due  to  the  entanglement  of  air  in  the  metal 
when  liquid,  and  occur  chiefly  in  the  upper  portions  of 
castings,  while  drawing  may  occur  anywhere,  and  has  no 
relation  whatever  to  the  pressure  of  air.  The  two  are 
totally  distinct  in  cause  and  in  appearance. 

It  is  not  easy  to  fix  the  most  suitable  amount  of  head- 
metal  for  a  given  job  right  off  without  experiment ; 
usually,  however,  previous  castings  of  a  similar  character 
afford  some  guide,  but  every  one  must  stand  on  its  own 
merits.  A  difference  in  design  necessitates  a  difference  in 
head-metal;  the  more  disproportionate  the  sections  of  a 
casting  the  heavier  should  the  head-metal  be. 

Since  the  head-metal  becomes  the  dirt  receptacle— 
the  feeder  for  its  casting,  that  determines  its  mass  in 
relation  to  the  casting:  it  must  be  large  enough,  but 


212  PRACTICAL  IRON  FOUNDING 

there  is  no  advantage  in  increasing  its  mass  unduly. 
But  if  it  is  insufficient,  some  of  the  dirt,  instead  of  passing 
up  into  the  head,  will  become  lodged  against  the  face  of 
the  casting.  If  the  mass  of  metal  in  an  annular  section 
of  the  head  is  considerably  less  than  that  in  a  corre- 
sponding annular  section  of  the  body  of  the  cylinder 
it  will  cool  down  before  the  cylinder  cools,  and  will  thus 
be  unable  to  fulfil  its  function  of  a  feeder  of  hot  metal, 
viz.,  to  fill  up  the  cavities  caused  by  shrinkage  stresses. 
One  sometimes  sees  head-metal  put  on  in  this  fashion; 
but  it  is  of  so  little  value  that  the  casting  would  be  as 
well,  probably  better,  without  it. 

The  proper  form  for  head-metal  is  shown  in  Fig.  126, 
p.  198,  where  its  diameter  is  as  large  as  that  of  the 
cylinder  body,  and  where  there  is  a  good  radius  which 
facilitates  the  passage  of  dirt  upwards  from  the  flange, 
and  there  is  sufficient  height  and  mass  in  the  head  to 
cause  it  to  remain  hot  after  the  body  of  the  cylinder  has 
ceased  to  remain  liquid,  and  so  the  head  becomes  an 
efficient  feeder  as  well  as  dirt  collector.  Another  example 
occurs  in  Fig.  172,  c,  p.  254. 

The  idea  might  suggest  itself  that  the  head  would  be 
more  efficient  if  made  as  large  as  a  cylinder  flange,  but 
the  adoption  of  such  a  method  would  cause  the  whole 
flange  to  become  drawn,  or  open-grained,  due  to  the 
metal  becoming  drawn  away  from  the  interior  portions 
towards  the  outside  faces,  causing  then  either  holes,  or 
coarse  crystallisation,  by  either  of  which  the  flange  would 
become  weakened,  and  the  making  of  a  steam-tight  joint 
rendered  difficult.  The  heads  illustrated  are  fully  efficient, 
practically  no  dirt  can  lodge  on  the  portion  of  the  flange 
uncovered  with  head,  because  during  the  movements  of 
the  molten  metal  any  light  matters  which  do  hitch  there 


DRY  SAND  MOULDING  213 

become  moved  again  and  buoyed  up  into  the  head  round 
the  curved  edges.  The  practice  of  feeding  or  pumping, 
which  is  done  through  the  head,  see  p.  161,  also  assists  in 
such  movements,  besides  fulfilling  its  main  function  of 
carrying  down  supplies  of  hot  metal  from  the  head  into 
the  shrinking  body  of  the  casting  below. 

The  diameter  of  a  head  is  easily  settled :  it  is  not  so 
easy  to  settle  its  height,  and  no  rule  can  be  given.  It 
often  becomes  necessary  in  standard  work,  in  order  to 
secure  the  best  results,  to  increase  the  height  of  a  head, 
so  that  this  becomes  a  matter  solely  for  judgment  and 
experiment;  speaking  generally,  heads  of  from  4  in.  to 
6  in.  deep  are  suitable  for  cylinders  from  6  in.  to  12  in. 
bore;  from  12  in.  to  18  in.  or  20  in.  bore,  the  heads 
should  be  8  in.  or  9  in.  deep.  Over  these  sizes  the  heads 
may  average  a  foot  deep,  there  or  thereabouts,  an  inch 
or  two  more  or  less  in  height  being  of  little  moment.  I 
should  say  that  heads  of  10  in.  or  12  in.  deep  are  suffi- 
cient for  any  cylinders,  no  matter  how  large.  Heads  of 
15  in.  to  16  in.  deep  are  put  on  hydraulic  cylinders,  but 
then  they  have  to  stand  very  heavy  pressures.  For  engine 
cylinders,  the  heights  given  represent  good  safe  practice. 

Head-metal  will  not  feed  a  casting  properly  if  the 
casting  is  badly  proportioned ;  if  there  are  very  thick  and 
very  thin  parts  adjacent,  the  metal  in  the  thicker  por- 
tions will  inevitably  become  drawn  and  open.  It  has 
sometimes  been  necessary  to  enlarge  the  areas  in  certain 
localities  in  cylinder  passages  solely  to  reduce  the  amount 
of  metal  adjacent  and  so  prevent  drawing.  Many  draws 
are  never  seen  until  cylinders  have  leaked  and  been 
broken  up;  but  they  often  show  on  the  face  of  a  flange, 
and  may  even  run  from  the  flange  into  the  passage 
adjacent.  If  the  best  results  are  to  be  obtained  from 


214  PRACTICAL  IRON  FOUNDING 

head,  cylinders  must  be  so  proportioned  that  there  shall 
be  no  great  disparity  in  adjacent  thicknesses  of  metal. 
Thus,  lumps  of  metal  massed  in  the  vicinity  of  passages 
or  flanges  should  always  be  lightened  out;  this  is  not  a 
question  at  all  of  saving  a  bit  of  metal,  but  possibly  of 
saving  a  casting. 


CHAPTER  XI 

CORES 

THE  term  core,  used  in  a  general  way  at  least,  is  almost 
self  explanatory.  Any  central  portion,  or  a  portion  re- 
moved from  central  parts,  is  a  core.  But  in  foundry 
work  the  term  has  several  distinct  meanings,  defined  by 
the  prefixes,  green  sand  core,  dry  sand  core,  loam  core, 
chitting  core. 

The  term  green  sand  core  simply  denotes  the  central 
portions  of  those  moulds  which  are  made  directly  from 
the  pattern  itself,  without  the  aid  of  a  separate  core  box. 
Thus,  the  central  portion  of  a  plain  open  rectangular 
frame,  like  the  surface  boxes  used  for  hydrants  in  the 
streets,  would  yield  a  green  sand  core,  because  moulded 
from  the  pattern  itself,  and  the  sand  employed  would  be 
of  precisely  the  same  character  as  that  encircling  the 
pattern,  and  would  be  connected  therewith  by  rods,  nails, 
or  grids,  and  undergo  no  process  of  drying  whatever. 
These  portions,  though  termed  cores  (often  termed  cods 
also),  do  not  come  properly  under  the  present  heading. 
Metal  cores  for  chilling  the  holes  in  the  hubs  or  bosses 
of  wheels  may  also  be  disregarded  in  this  connection,  and 
also  those  loam  cores  which  are  bricked  up,  see  Chapter 
XII,  so  that  all  we  have  to  consider  in  this  chapter  is 
the  cores  made  in  dry  sand  in  core  boxes,  and  loam  cores 
which  are  struck-up  or  swept  up  on  bars. 

Cores  are  required  when  (a)  there  would  be  extreme 

215 


216  PRACTICAL  IRON  FOUNDING 

difficulty  in  so  constructing  a  pattern  that  an  impres- 
sion could  only  be  taken  of  the  central  portions  by 
making  a  large  number  of  joints  in  pattern  and  mould; 
(b)  when  the  central  sand  would  be  so  weak  that  it  would 
not  retain  its  form  and  position  against  the  rush  and 
pressure  of  metal;  (c)  when  the  cutting  out  of  the  in- 
ternal portions  of  patterns  would  render  them  excessively 
weak  as  patterns;  and  (d)  generally,  when  it  would  either 
be  impossible  or  extremely  difficult  to  make  or  put  the 
mould  together,  or  vent  it  without  the  aid  of  cores.  Thus, 
if  we  take  almost  any  pump  clack  box  or  valve  box  with 
seatings  we  could  make  a  pattern  precisely  like  the  cast- 
ing, making  as  many  joints  as  would  be  required  to  allow 
of  drawing  the  parts  separately  from  the  mould.  But  we 
should  then  meet  difficulty  (a)  and  also  (c).  But  the  sub- 
stitution of  a  simple  core  or  cores  enables  us  to  make  a 
strong  pattern,  and  to  employ  one  or  two  joints  only,  in- 
stead of  several,  in  the  mould.  Or,  if  holes  of  small  area, 
but  of  considerable  length,  are  required  in  castings,  green 
sand  would  not  deliver  freely  from  similar  holes  made  in 
the  pattern,  but  would  become  cracked  and  broken  away, 
even  if  a  considerable  amount  of  taper  were  imparted ; 
neither  would  they  withstand  the  rush  of  metal.  Then 
the  conditions  (b)  necessitate  the  use  of  dry  hard  cores. 
And  no  more  familiar  example  of  condition  (d)  could  be 
given  than  that  of  any  engine  cylinder  with  its  passages 
and  feet,  and  often  other  attachments  beside. 

It  is  clear  that  the  same  conditions  must  exist  in  cores 
as  in  the  moulds  themselves.  The  substance  of  cores 
must  be  stiffened  with  rods,  grids,  or  nails,  precisely  on 
the  same  principles  as  moulds,  though  the  conditions 
and  details  are  somewhat  different.  Vents  of  sufficient 
area  must  be  provided  to  carry  off  gas  and  air,  and  the 


GORES  217 

cores  must  be  secured  against  the  pressure  of  liquid  metal. 
These  are  all  points  of  fundamental  importance,  and  we 
will  consider  them  in  detail. 

First,  in  regard  to  the  stiffening  of  cores.  In  a  plain 
round  core  made  in  a  box,  a  rod  of  iron  is  rammed  up 
with  it,  and  this  is  the  simplest  plan.  In  crooked  cores 


FIG.  135.— STEAM  FIG.  136.— A  GRID. 

PASSAGE  CORE. 

the  rods  are  either  bent,  as  in  Fig.  135,  which  illustrates 
the  passage  core  of  an  engine  cylinder,  or  grids  are 
formed  of  wires  or  rods  fastened  together  with  solder.  In 
large  cores,  grids  are  always  used,  like  Figs.  136  and  137, 
having  nuts  or  eyes  by  which  to  lift  them.  These  grids 
may  be  of  any  outline,  being  adapted  to  their  cores. 


FIG.  137.— A  GRID. 

Fig.  136  shows  one  of  a  sweeped  outline  adapted  to  a 
sweeped  core,  Fig.  137  one  of  triangular  outline;  Fig.  136 
has  a  nut,  A,  cast  in  to  take  the  screw  used  for  lifting, 
Fig.  137  has  a  couple  of  eyes  cast  in  for  the  same  purpose. 
These  are  usually  cast  in  open  sand,  the  moulder  using 
a  standard  pattern  grid,  having  excess  of  length,  and 
stopping  it  off  to  length  and  outline  required.  In  large 


218  PRACTICAL  IRON  FOUNDING 

and  intricate  work  several  distinct  grids  may  be  bolted 
together,  the  bolts  being  so  placed  that  they  may  be 
readily  taken  out  after  the  casting  is  made,  through  open- 
ings in  the  cored  out  sides  of  the  casting  itself. 

Fig.  138  shows  a  grid  used  for  a  pipe  core  made  in  a 
core  box,  a  grid  being  used  in  each  half  core.  Similar  grids, 
curved,  are  used  for  bend  pipes  of  large  diameter,  the 
longitudinal  portion  stiffening  the  core,  and  the  offsets  or 
prongs  giving  local  support  to  the  sand.  Stiffeners  and 
grids  of  this  kind  are  used  both  for  cores  rammed  in  core 
boxes,  and  for  those  strickled  up  on  plates.  But  there  is 
a  large  class  of  cores  which  are  not  made  in  boxes,  but 
struck  up  on  revolving  bars.  The  bars  then  act  as  stiff- 

I    |  •  I  I  •  I  • 

FIG.  138.— PIPE  GRID. 

eners  longitudinally,  and  the  core  is  made  in  loam,  the 
adhesion  of  which  to  the  bar  is  assisted  by  the  use  of 
hay  bands  or  hay  ropes,  twisted  and  wound  around  the 
bar.  When  cores  are  very  large  the  bar  is  not  increased 
directly  in  proportion,  except  for  certain  standard  work, 
but  is  selected  simply  with  a  view  to  sufficient  stiffness, 
and  the  size  of  the  core  is  increased  by  the  addition  of 
hay  bands  and  loam  alternating  with  each  other,  and 
sustained  with  core  plates  A,  Figs.  139  and  140.  In 
standard  pipe  and  column  work,  collapsible  core  bars  are 
used. 

There  is  thus  a  very  wide  range  in  the  size  and  char- 
acter of  the  bars  employed.  The  smaller  ones  are  made 
of  gas  piping;  for  those  over  about  3  in.  in  diameter, 
cast  iron  cylinders  are  employed,  and  these  may  be 


CORES 


219 


either  parallel  or  tapered,  according  to  the  character  of 
the  work.  The  bars  are  invariably  hollow,  and  pierced 
with  numerous  small  holes,  Fig.  139,  for  the  air  vents, 
which  pass  from  the  encircling  core  through  the  holes  to 
the  interior  of  the  bar,  whence  they  find  exit  at  the  ends. 
The  bars  are  turned  next  the  ends,  Fig.  139,  B,  to  form 
journals,  which  revolve  in  vees  on  the  cast  iron  trestles 
used  for  their  support.  A  boy  turns  at  a  winch  handle 


B 


A  A  A 

FIG.  139. — CORE  BAR  AND  PLATES. 


*  *•**»*•*.*•*•   I 

•  • .    .*•„*.    -  .  »t 


FIG.  140. — SECTION  THROUGH  FINISHED  CORE. 

inserted  in  one  end  of  the  bar,  while  the  core  maker 
winds  on  the  hay  bands,  and  daubs  the  loam.  This  is 
work  requiring  the  exercise  of  judgment.  If  the  bands 
are  not  pulled  taut,  and  laid  on  close,  and  the  loam 
well  worked  into  the  interstices,  the  core  will  sag,  or 
become  baggy,  will  be  out  of  truth,  and  dry  unequally 
in  different  parts,  and  portions  of  the  loam  may  flake 
off  after  drying.  A  layer  of  rope  is  laid  on  first,  and 
stiff  loam  well  worked  over  and  between  it  as  the  bar 


220 


PRACTICAL  IRON  FOUNDING 


revolves,  then  another  layer  of  rope  and  more  loam,  Fig. 
140.  The  core  is  partially  dried  before  putting  oil  the  final 
coat,  which  is  thinner  than  that  first  applied.  Fig.  141 
shows  a  section  through  a  core  bar  A,  hay  bands  B, 
and  finishing  coat  of  loam,  C.  D  indicates  vent  holes. 
When  plates  are  employed,  as  in  Figs.  139  and  140,  they 
are  cast  as  thin  as  possible,  and  pierced  with  holes,  as 
shown,  to  permit  of  their  ready  fracture  and  withdrawal 
after  casting.  When  very  large,  the  various  plates  are, 

in  addition  to  the  usual 
fastening  to  the  bars  by 
means  of  wedges,  united 
and  stiffened  with  bolts 
passing  through  them  all, 
the  bolts  being  inserted 
when  the  final  course  of 
hay  bands  is  being  wound 
round,  and  the  nuts  are 
brought  for  convenience  of 
withdrawal  opposite  suit- 
able vent  holes  in  the  ends 
of  the  casting. 

These    core   bars   when 

of  small  diameter  are  used  for  light  work,  and  when 
large,  mainly  for  jobbing  work.  In  regular  or  repeti- 
tion work  of  large  diameter,  as  in  many  pipes  and 
columns,  the  cost  of  hay  bands  and  of  rigging  up 
core  plates  would  bear  too  great  a  proportion  to  the 
value  of  the  castings.  In  standard  pipe  work  therefore, 
and  in  other  work  of  that  character,  the  collapsible  bars 
are  employed.  These  are  only  \  in.  or  1  in.  less  in  dia- 
meter than  the  finished  cores  which  they  carry,  and  are 
therefore  necessarily  made  collapsible,  that  is,  they  are 


FIG.  141. — SECTION  OF  CORE 
AND  BAR. 


•COBE8  221 

so  constructed  as  to  fold,  or  fall  inwards,  and  so  deliver 
freely  from  the  cored  holes.  Much  ingenuity  has  been 
displayed  in  their  design,  and  several  forms  are  in  use. 
The  general  principle  of  their  action  is  this:  The  shell  is 
usually  formed  of  three  longitudinal  segments  of  cast 
iron,  two  of  which  are  hinged  loosely  upon  the  third  or 
rigid  piece.  The  movable  segments  are  retained  in  their 
expanded  condition  during  the  making  of  the  core,  and 
pouring  of  the  casting,  by  various  devices,  as  by  circular 
discs,  or  by  wedge-shaped  bars  and  links,  adapted  to 
similar  fittings.  By  means  of  cottars,  levers,  and  links, 
the  movable  segments  are  released,  falling  inwards  after 
the  casting  is  made.  The  body  of  the  bar  is  pierced  with 
vent  holes.  The  outside  of  a  collapsible  bar  is,  like  an 
ordinary  bar,  left  rough,  the  better  to  ensure  the  ad- 
hesion of  the  loam,  which  is  daubed  on  directly,  without 
the  intervention  of  hay  bands. 

The  vents  of  cores  are  variously  contrived,  and  are  of 
the  first  importance,  since  many  a  casting  is  ruined  for 
want  of  proper  venting  and  securing  of  the  core  vents. 

The  simplest  vent  is  that  formed  in  a  plain  core  by 
means  of  a  rod  of  iron  rammed  therein,  and  withdrawn, 
leaving  a  round  hole,  into  which  the  air  and  gas  gen- 
erated within  the  core  collects,  and  from  which  it  finds 
exit  through  the  prints.  In  large  cores  numerous  rods 
will  be  rammed  in,  and  withdrawn  thus;  and  in  addi- 
tion to  these,  a  quantity  of  smaller  vents  will  be  made 
with  the  vent  wire,  as  in  making  moulds.  In  curved 
cores  (Figs.  142  and  143)  a  different  method  has  to  be 
adopted.  Core  strings  or  core  ropes  have  to  be  used,  being 
common  string  or  rope  rammed  up  in  the  core,  and  either 
withdrawn  while  the  core  is  yet  green,  or  allowed  to  re- 
main while  the  core  is  being  dried;  which  process  of 


222  PRACTICAL  IRON  FOUNDING 

baking  chars  the  string,  and  allows  of  its  fragments 
being  blown  out  with  the  bellows.  The  latter  method 
is  rather  uncertain,  so  that  the  better  plan  is  to  with- 
draw the  string,  the  core  being  green,  in  which  case 
two  bits  of  wire  rammed  in  the  core,  Fig.  142,  prevent 
the  string  from  cutting  the  corners  .by  its  tendency  to 
straighten  under  tension.  An  alternative  plan  which  is 
often  adopted  is  that  shown  in  Fig.  143,  where  three 
straight  rods  are  rammed  up  in  the  core,  drawn  out,  and 
the  core  dried.  Then  the  connection  is  made  round  the 
curve  by  filing,  a  string  inserted,  and  daubed  and  covered 


FIG.  142. — CORE  STRING.         FIG.  143. — VENTING  EODS 

IN  CORE. 

over  with  loam.  This  is  then  dried,  and  the  string  finally 
withdrawn. 

In  the  case  of  large  cores  the  central  portions  are 
formed  of  cinders,  to  act  as  reservoirs  for  the  air  and 
gas,  precisely  as  in  the  bulkier  sections  of  green  sand 
and  dry  sand  moulds.  A  vent  hole  or  holes  of  sufficient 
area  is  then  made,  connecting  this  body  of  cinders  with 
the  outer  air. 

In  cores  struck  on  bars,  the  hay  is  porous,  and  con- 
ducts the  air  into  the  central  core  bar,  which  is  in- 
variably made  hollow  and  pierced  with  numerous  holes 
for  that  purpose.  But  there  is  no  venting  done  with 
the  wire  in  struck-up  cores,  as  there  is  with  those 
made  in  boxes.  The  latter  are  pierced  with  vent  holes 


CORES  223 

similarly  to  moulds,  but  the  hay  bands  and  loam  are, 
when  dried,  sufficiently  porous  in  themselves. 

Cores  are  fastened  and  their  vents  secured  in  several 
different  ways.  In  most  cases  they  are  set  in  print  im- 
pressions, but  not  invariably.  If  a  core  is  large  and 
heavy,  prints  are  not  necessary.  Still,  in  the  vast  majority 
of  cases  they  are  employed. 

The  forms  of  prints  are  various,  depending  on  the 
position  and  mode  of  support  required.  Cores  may  rest 
in  the  bottom  of  a  mould,  or  be  carried  in  the  top,  or 
at  the  sides,  or  be  bridged  across  from  one  portion  to 
another.  They  may  be  carried  by  print  impressions  made 
in  other  cores.  A  core  may  be  carried  by  one  print  only, 
or  it  may  have  several  points  of  support. 

Generally  the  rule  is  this.  A  core  laid  in  the  bottom 
is  sustained  by  the  bottom  print  only,  the  exception 
occurring  when  the  core  is  so  long  relatively  to  its  area 
that  a  bottom  print  alone  would  not  afford  it  sufficient 
steadiness  of  base.  In  that  case  a  top  print  will  be  used, 
or  chaplet  nails,  or  perhaps  both  in  combination.  But  if 
the  core,  though  long,  has  a  broad  base  sufficient  to 
afford  steadiness,  than  neither  top  print  nor  chaplet 
nails  are  required.  A  core  carried  at  the  side,  if  short 
relatively  to  its  area,  will  need  no  other  support  than  the 
side  print.  If  long,  it  also  must  be  supported  by  chaplet 
nails,  or  if  it  passes  right  across  a  mould,  by  a  print  on 
each  side.  Cores  carried  at  the  sides  may  be  either  sus- 
tained by  prints  of  the  same  kind  as  those  used  in  top 
and  bottom,  or  in  pocket  or  drop  prints,  dependent  on  cir- 
cumstances. Pocket  prints  are  employed  when  the  joint  of 
the  mould  does  not  coincide  with  the  centre  of  the  hole. 
In  such  a  case  as  Fig.  144,  if  a  round  print  were  used  it 
would  have  to  be  skewered  on  loosely,  and  the  core 


224 


PRACTICAL  IRON  FOUNDING 


thrust  in  afterwards,  which  in  this  case  could  not  be 
done,  the  core  being  unable  to  pass  down  by  A ;  or  the 
cope  sand  would  have  to  be  jointed  down  around  the 
dotted  line  B,  to  the  centre  of  the  print,  which  in  deep 
or  in  moderately  deep  lifts  would  be  very  inconvenient. 
Using  a  pocket,  or  '  drop  print,'  the  lift  takes  place  to 


FIG.  144. — POCKET  PRINT. 

the  cope  joint  C,  leaving  a  clear  open  space  into  which 
to  drop  the  core,  which  is  then  filled  over  with  sand,  a 
stopping  over  board,  Fig.  145,  A,  cut  to  clip  the  core, 
being  held  against  the  mould  face  while  the  space,  B, 
above  the  core  is  rammed  with  sand.  The  core  is  then 
permanently  secured  as  though  in  a  round  print. 


1 


FIG.  145. — STOPPING  OVER. 

But  core  setting  embraces  very  much  besides  this.  It 
is  not  always  sufficient  in  large  cores  to  trust  to  the 
pressure  of  contiguous  sand  for  security.  There  is  an 
enormous  liquid  pressure  in  large  moulds,  and  this 
would,  in  the  absence  of  due  precautions,  force  the  cores 
bodily  out  of  place  in  their  central  portions,  even  if  well 
secured  at  the  ends  in  their  prints;  or  would  carry  them 


PLATE  IX 


See  p.  286 


FIG.  197. — PRIDMORE  MACHINES 


See  p  290  [Facing  p.  224 

FIG.  201. — A  PRIDMORE  MACHINE,  FITTED  WITH  STEAM 
PUMP  PATTERN 


CORES  225 

away  from  their  prints  if  simply  laid  therein.  A  pipe 
core,  or  a  column  core,  for  example,  would  be  bent  and 
curved  upwards  until  it  would  nearly  or  quite  touch  the 
top  of  the  mould.  A  flat  core  with  metal  over  its  top 
face,  and  having  therefore  open  space  between  it  and  the 
cope  sand,  would  be  floated  up  by  the  metal,  and  cause 
a  waster  casting.  Chaplet  nails,  chaplets,  and  stops  are 
therefore  employed  to  steady  cores  in  their  proper  posi- 
tions. The  forms  and  sizes  of  these  vary  with  their  posi- 
tion and  function.  Figs.  146  to  153  show  chaplets  in  situ. 
In  Fig.  146,  B',  is  a  chaplet  nail  driven  into  a  block  of 
wood,  A',  to  afford  breadth  and  steadiness  of  base  in  the 
yielding  sand.  The  height  of  this  nail  is  adjusted  to  the 
thickness,  B,  of  metal  required.  Upon  the  flat  head,  C', 
of  the  nail  rests  the  core,  C.  Fig.  147  shows  another 
chaplet  made  by  riveting  a  bit  of  iron  rod,  B',  into  a 
flat  plate,  A',  and  used  for  a  heavier  class  of  work  than 
the  common  chaplet  nail.  Here  .4  is  the  core  the  upward 
thrust  of  which  is  sustained  by  the  flat,  A',  of  the  chaplet, 
which  passes  through  the  cope  sand,  B,  being  supported 
either  against  the  inside  face  of  a  flat  bar  of  the  flask,  or 
a  bar  of  iron,  C,  placed  temporarily  across,  as  shown,  to 
fulfil  the  same  purpose.  D  is  the  thickness  of  metal 
between  the  upper  face  of  the  core,  A,  and  the  lower  face 
of  the  cope,  B.  Fig.  148  shows  another  chaplet  which 
lies  entirely  between  core  and  mould  faces,  and  having 
a  thickness  equal  to  the  thickness,  A,  of  the  metal.  In 
large  heavy  moulds  these  chaplets  will  be  of  correspond- 
ingly large  area,  so  that  two  or  three  stalks  may  be 
required  to  connect  the  plates,  Fig.  149.  In  light 
work  not  subject  to  much  pressure,  spring  chaplets  are 
used,  consisting  of  pieces  of  hoop  iron  bent  round. 
These  are  retained  in  place  by  their  elasticity,  and  are 

Q 


226 


PRACTICAL  IRON  FOUNDING 


mostly  used   against  vertical  or  nearly  vertical  faces, 
Fig.  150. 

Chaplets  have  their  faces  curved  when  they  abut  against 


FIG.  146.— CHAPLET.  FIG.  147.— CHAPLET. 


FIG.  148. 
CHAPLET. 


FIG.  149.—  TRIPLE 
STUD  CHAPLET. 


FIG.  150. 
SPKING  CHAPLET 


FIG.  151.— PIPE 
CHAPLET. 


FIG.  152.— PIPE 
CHAPLET. 


FIG.  153. 

STOP. 


curved  faces.  Figs.  151,  152,  show  two  such  forms,  modi- 
fications of  Figs.  146,  147.  The  core  rests  upon  the 
stud  in  Fig.  151,  but  in  Fig.  152  the  stud  is  introduced  to 
resist  the  upward  pressure  of  the  core.  Fig.  153  shows  a 
stop  employed  when  the  mould  is  subject  to  very  great 


CORES  227 

pressure.    It  is  made  of  cast  or  wrought  iron,  and  turned 
bright,  or  ground. 

The  evil  of  stops  and  chaplets  is  their  tendency  to 
cause  blow  holes  in  their  vicinity.  Should  they  become 
rusty  the  mould  is  absolutely  certain  to  blow  very  badly, 
owing  to  the  formation  of  gaseous  compounds  from  the 
rust.  Chaplet  nails  are  often  tinned  to  prevent  rust. 
With  the  same  object  wrought  iron  chaplets,  made  by 
the  foundry  smith,  are  heated  to  redness  in  the  fire  and 
brushed  over  with  tar  or  oil.  Oil  is  also  poured  around 
and  over  chaplets  while  in  place  to  prevent  formation 
of  rust  during  the  time  intervening  before  casting,  and 
to  cause  the  iron  to  lie  quietly  on  the  cold  metal.  In  all 
but  the  thinnest  castings  the  chaplet  stalks  become  more 
or  less  fused  by  the  metal  surrounding  them.  But  the 
heads  usually  remain  visible,  and  do  not  amalgamate 
properly.  Hence  chaplets  should  never,  if  it  can  be 
avoided,  be  placed  against  faces  or  parts  which  have  to 
be  bored  or  turned. 

It  is  not  only  necessary  to  fix  and  properly  vent  cores, 
but  to  secure  the  vents  as  well,  that  is,  to  see  that 
adequate  provision  is  made  for  the  escape  of  the  air  and 
gas  from  the  interior  of  the  core  to  the  outer  atmosphere. 
The  vent  openings  must  be  so  secured  that  there  shall 
be  no  chance  of  the  entry  of  the  molten  metal  into  them. 
If  it  gets  in,  the  gas  will  not  come  out,  and  the  casting 
will  blow,  and  become  a  waster.  A  chapter  could  well  be 
entirely  devoted  to  this  subject  of  securing  of  vents,  so 
important  is  it,  and  so  many  are  the  methods  adopted  to 
attain  this  end,  but  we  must  be  content  to  note  a  few 
leading  points  bearing  thereon.  Thus,  it  is  risky  to  bring 
core  vents  off  against  an  abutting  face  simply,  unless 
means  are  taken  to  prevent  any  possibility  of  the  pres- 


228  PRACTICAL  IRON  FOUNDING 

sure  of  metal  causing  an  opening  between  the  faces  to 
occur.  There  is  less  risk,  however,  in  horizontal  than  in 
vertical  faces,  and  of  the  two,  a  lower  horizontal  face  stands 
less  risk  than  an  upper  one,  because  the  cope  is  liable 
to,  and  does  usually,  lift  slightly.  Where  vents  are  carried 
down  through  the  bottom,  they  are  taken  into  a  coke  bed, 
as  already  explained,  p.  164,  and  thence  out  through  a 
vent  pipe  or  pipes.  When  they  are  brought  into  the  cope, 
they  are  usually  carried  into  one  or  two  large  holes  cut 
through  the  cope  sand. 

But  prints  afford  the  best  means  of  securing  cores, 
because  if  any  slight  separation  of  the  core  and  mould 
occurs  under  pressure,  the  metal  cannot,  if  the  core  and 
print  are  mutually  good-fitting,  run  between  them  into 
the  vents.  Properly  the  cores  should  be  cemented  into 
their  prints  by  means  of  core  sand,  or  of  black  wash. 
This  is  usually  done  only  in  the  most  important  work. 
In  most  cases  it  is  sufficient,  after  the  core  has  been 
thrust  into  its  print,  to  press  and  consolidate  sand  around 
and  into  the  joint. 

When  distinct  cores  meet  each  other  in  the  mould, 
vents  should  only  be  carried  from  one  into  the  other 
when  they  can  be  secured  through  a  print  impression,  one 
thus  being  checked  into  the  other.  When  the  joint  is 
only  a  butt  joint,  then  the  core  vents  must  be  filled  with 
sand  immediately  against  the  abutting  faces,  and  the  air 
be  brought  away  at  the  opposite  ends,  where  the  cores  fit 
the  print  impressions  of  the  mould  itself. 

In  the  case  of  cores  struck  upon  revolving  core  bars, 
the  air,  after  being  brought  into  the  bars,  is  carried  out 
at  the  ends. 

Cores  are  dried  in  stoves  or  ovens  heated  with  coke 
fires  or  gas.  The  smaller  cores  are  dried  in  ovens  having 


CORES 


229 


a  capacity  of  a  few  cubic  feet  only;  for  the  larger  ones, 
stoves  of  from  18  ft.  to  24  ft.  long,  10  ft.  to  14  ft.  wide, 
and  10  ft.  to  12  ft.  in  height,  are  employed.  These  are 
built  of  brickwork,  and  furnished  with  folding  or  sliding 
doors.  The  cores  are  laid  upon  a  core  carriage,  which  is 


FIG,  154. — TUYERE  CASTING. 


a  low  iron  carriage  running  on  tram  rails,  and  provided 
with  suitable  supports  for  the  ends  of  the  core  bars,  and 
with  flat  plates  for  cores  made  in  boxes,  and  those  formed 
with  strickles.  A  temperature  of  about  400°  is  suitable 


FIG.  155. — PATTERN  OF  TUYERE. 

for  the  drying  of  cores :  excess  of  heat  burns  the  hay,  and 
makes  the  sand  or  loam  rotten  and  friable. 

The  illustrations  show  the  pattern-work  and  moulding 
for  a  small  tuyere,  selected  because  it  is  an  example  of 
double  coring. 

Fig.  154  shows  the  tuyere  casting  in  longitudinal  sec- 
tion, and  the  pattern- work  and  moulding  are  illustrated  in 
subsequent  Figs.  Looking  at  Fig.  154  it  is  seen  that  there 


230 


PRACTICAL  IRON  FOUNDING 


are  two  cores  entirely  unconnected,  A  being  that  for  the 
blast  passage,  B  that  for  the  water  chamber.  The  tube 
containing^  is  cast  to  the  outer  body  at  the  fire  end;  at  the 
other  it  is  connected  to  the  body  with  a  shallow  bridge  of 
metal,  C.  In  moulding  this  a  plain  pattern  is  used,  Fig. 
155,  having  a  print  at  each  end,  and  two  separate  cores 
are  employed  for  taking  out  the  interior.  As  these  cores 
must  be  maintained  concentrically,  provision  is  made  for 
this  in  the  manner  shown  in  Figs.  156  and  157. 

Fig.  156  is  a  plan  view  of  the  core-box  in  the  joint-face. 
As  the  core  is  absolutely  symmetrical,  one  half-box  only 


.  156.  —  CORE  Box  FOR  TUYERE. 


is  made.  The  main  portion  is  cut  through  with  planes 
to  the  bounding  lines  of  the  body  core,  and  the  ends 
are  screwed  on  separately,  as  indicated  by  the  direction 
of  the  grain  of  the  timber.  The  large  end  of  the  core- 
box  is  extended  to  correspond  with  the  core  print  A  in 
Fig.  155,  which  insures  the  concentricity  of  the  body  core 
in  the  mould  (see  Fig.  157).  The  similar  disposition  of 
the  water  tube  and  its  core  is  determined  by  cutting 
holes,  one  at  each  end  of  the  core-box,  by  which  the 
tube  piece  is  centred  and  its  core  by  the  print  B  on  the 
pattern,  Fig.  155,  and  by  the  print  E  turned  on  the 
tube-piece  in  Fig.  156.  The  bridge-piece.  C',  Fig.  154, 


CORES 


231 


which  connects  the  tube  to  the  body,  is  rebated  into 
the  tube-piece  in  Fig.  156,  and  drops  into  shallow  re- 
cesses in  the  sides  of  the  core-box.  The  flange  D  in 
Fig.  154,  to  which  the  blast-pipe  is  bolted,  is  seen  should- 
ered over  the  tube-piece  in  Fig.  156.  Everything,  there- 
fore, is  central,  and  nothing  can  become  displaced  during 
ramming  of  the  core. 

The  two  half-cores  made  from  the  box  in  Fig.  156  are 
not  cemented  together.  Each  is  vented  separately,  the 
vents  being  brought  out  through  the  print  ends  at  A, 


FIG.  157. — OPEN  MOULD  OF  TUYERE. 

Fig.  155.  The  main  cores  are  carried  at  one  end  only  in 
a  print  impression — at  the  end  A.  At  the  opposite  end, 
chaplets  are  inserted  to  support  them  centrally.  The 
middle  core  for  the  water  passage  is  perfectly  straight, 
and  is  lowered  into  its  print  impressions  in  core  and 
mould  in  the  bottom  box.  The  top  half-core  and  mould 
are  lowered  over  it. 

The  same  principles  which  govern  the  construction  of 
patterns  must  be  regarded  in  the  construction  of  core 
boxes.  Thus,  regard  must  be  had  to  taper  and  such  ar- 
rangements of  loose  pieces  as  permit  of  ready  withdrawal, 
strength  of  parts,  economy  of  material,  and  so  forth. 


232  PRACTICAL  IRON  FOUNDING 

Further,  it  is  always  best  when  practicable  to  avoid  the 
turning  over  of  heavy  cores,  which  is  apt  to  cause  their 
fracture.  In  most  cases  it  is  quite  as  easy  to  make  the 
box  so  that  the  core  shall  be  rammed  up  just  as  it  has  to 
stand  in  the  mould — that  is,  top  side  up — as  in  any  other 
way.  Especially  is  this  precaution  necessary  when  grids 
and  eyes  are  in  question,  the  eyes  being  required  upper- 
most for  lifting  the  cores  by.  The  patternmaker  should 
bear  this  in  mind  when  making  his  boxes. 

There  are  many  cores  rammed  in  boxes  which  are  sym- 
metrical; and  in  these  cases  a  half-box  suffices,  and  a 
considerable  saving  is  effected  in  material  and  cost  of 
work  in  the  pattern  shop.  Take  a  core  like  that  shown 
in  Fig.  157  as  typical  of  a  numerous  class  in  which  both 
halves  are  precisely  alike;  hence  two  halves  are  rammed 
separately,  the  joint  faces  sleeked  level  and  united  either 
while  green  or  dry.  In  such  cases  each  half  of  the  core 
requires  its  separate  grid.  Taking  a  core  which  is  united 
while  green  one  half  is  first  rammed  in  the  box,  bedding 
in  during  the  process  the  "grid"  or  "core  iron";  and 
in  cases  where  there  are  thin  sections  of  sand,  nails  are 
put  in  precisely  as  in  the  weak  portions  of  moulds.  The 
sand  is  made  complete  to  the  joint  face,  and  then  a 
vent  channel,  rudely  semicircular  in  section,  is  cut  with 
the  trowel.  If  the  core  is  of  large  size — or  when  small, 
if  the  sand  is  close — vents  are  driven  from  this  channel 
radially  to  the  inside  faces  of  the  box.  But  if  the  core  is 
small  and  the  sand  is  open,  there  is  no  need  to  do  so. 
The  half-core  is  now  lifted  out  with  the  grid  and  laid 
with  its  convex  face  downwards  upon  a  bed  of  soft 
moulding  sand.  The  corresponding  half-core  is  then 
similarly  made,  turned  over,  and  pressed  down  on  the 
joint  face  of  the  first,  the  moisture  and  slight  pressure 


CORES  233 

causing  adhesion.  The  union  is  frequently  assisted  by 
sticking  nails  upward  in  the  joint  and  allowing  them  to 
enter  at  equal  distances  into  both  halves.  When  the 
cores  are  made  in  halves,  and  united  after  drying,  they 
are  stuck  with  a  wash  of  clay-water  or  of  "slurry" 
made  of  thin  loam  and  water.  When  cores  which  are 
unsymmetrical,  but  of  circular  section,  are  made  in 
complete  boxes,  they  are,  if  of  moderate  or  considerable 
length,  rammed  in  halves  and  squeezed  together  with  or 
without  a  thin  wash  of  clay-water  intervening.  Such 
cores  must  be  turned  over  and  laid  while  green  on  a 
bed  of  soft  moulding  sand  before  being  put  into  the 
stove  to  dry. 

A  convenient  mode  of  turning  a  core  over  without 
damaging  it  when  a  large  number  are  required  is  to  use 
a  light  frame  of  wood,  or  preferably  of  iron,  which  is 
placed  upon  a  quantity  of  loose  green  sand  thrown  upon 
the  finished  core,  thus  confining  the  sand  in  place.  The 
frame,  core  and  half-box  are  turned  bodily  over,  and  the 
half-box,  then  uppermost,  is  lifted  away,  leaving  the 
core  resting  upon  the  soft  cushion  of  sand  confined  by 
the  frame.  It  is  very  simple,  and  often  saves  the  fracture 
of  delicate  cores. 


CHAPTEK  XII 

LOAM  WORK 

THE  advantage  of  loam  moulding  consists  in  the  facilities 
which  it  affords  for  making  castings  of  the  most  massive 
character  without  incurring  much  expense  for  pattern 
making.  The  apparatus  used  is  of  the  most  simple  de- 
scription, consisting  of  spindle,  bar,  and  striking  boards; 
the  materials  being  loam,  bricks,  and  cinders:  with  the 
aid  of  these  the  largest  and  heaviest  castings  are  made. 

Loam  work  is  a  specialized  branch,  which  all  moulders 
have  not  had  an  opportunity  of  acquiring,  hence  its  ex- 
clusiveness ;  but  it  is  not  more  intrinsically  difficult 
than  the  other  branches.  I  am  inclined  to  think  it  easier 
of  acquisition;  but  here,  as  in  many  other  instances,  the 
question  is  one  of  supply  and  demand,  rather  than  of 
special  difficult}7.  Also,  large  loam  moulds  are  costly,  and 
men  are  paid  then  for  their  care,  as  well  as  skill  and 
special  knowledge.  The  mould  for  a  condenser,  or  for  a 
large  cylinder,  will  often  occupy  a  couple  or  three  men 
for  nearly  a  month,  hence  the  matter  of  two  or  three 
days'  time,  more  or  less,  is  of  small  account  in  com- 
parison with  the  soundness  of  the  casting. 

The  art  of  loam  moulding,  after  the  first  principles  are 
mastered,  lies  in  the  exercise  of  the  inventive  faculty,  the 
ability  to  scheme  the  best  methods,  to  elaborate  the 
safest,  and  on  the  whole  the  cheapest  tackle:  to  conceive 
the  main  plan,  and  to  execute  the  lesser  details  with  a 

234 


LOAM  WORK  235 

clear  head,  guided  by  the  lessons  born  of  experience. 
Loam  moulding  is  an  art  in  itself,  and  a  man  who  can 
undertake  any  job,  large  and  small,  devise,  and  make,  and 
rig  up  his  tackle,  and  produce  uniformly  safe  results, 
need  never  swell  the  ranks  of  the  unemployed — he  is  in- 
dispensable. 

It  is  a  great  advantage  to  a  loam  moulder  to  be  able 
to  read  a  drawing  correctly.  If  he  cannot  do  so,  he  has, 
in  intricate  work,  to  depend  on  the  explanations  of  the 
pattern  maker  before  he  can  set  about  his  task,  or  even 
decide  how  to  do  it,  or  line  out  his  centres.  Some  loam 
moulders  are  quite  independent  of  the  pattern  maker  in 
this  respect,  doing  all  the  lining  out  themselves. 


FIG.  158. — BASE  FOR  ENGINE  CYLINDER. 

So  much  may  be  said  about  loam  work,  so  many  differ- 
ent cases  may  arise  in  practice,  that  the  best  way  will  be 
to  take  some  concrete  and  plain  examples  and  make  them 
the  vehicle  for  remarks  on  loam  moulding  in  general. 

The  example  selected  in  Fig.  158  is  the  base  which 
forms  the  bottom  cover  of  the  cylinder  of  a  condensing 
beam  engine.  The  top  face  A,  as  the  casting  stands  when 
in  position,  is  moulded  and  cast  downwards,  to  ensure 
soundness. 

The  apparatus  used  is  as  follows:  in  Fig.  159,  A  is 
the  striking  bar,  B  its  socket.  The  socket,  of  cast  iron, 
is  firmly  embedded  in  the  floor  and  levelled,  its  broad 
bracketed  face  maintaining  it  sufficiently  steady.  It  is 


236  PRACTICAL  IRON  FOUNDING 

bored  out  to  receive  the  turned  tapered  end  of  the  bar, 
or  it  is  cast  around  the  turned  tapered  end,  in  either 
case  making  a  close,  yet  working  fit.  The  tapered  end 
is  long,  so  that  as  the  bar  revolves,  its  top  end  shall  not 
diverge  sensibly  from  the  perpendicular.  Over  the  bar 
slides  freely  the  strap  (7,  which  is  pinched  at  any  required 
height  with  its  set  screw.  To  the  strap  is  bolted  the 
striking  board  or  loam  board  D,  the  profile  of  the  edges 
of  which  corresponds  in  the  main,  though  not  in  all  de- 
tails, with  the  sectional  shape  of  the  casting  required. 
F  is  the  loam  plate  or  building  up  plate,  made  of  cast 
iron  in  open  sand,  without  a  pattern,  by  means  of  sweeps 
only. 

Fig.  159  represents  an  early  stage  of  operations.  The 
socket,  B,  is  set  in  place,  the  loam  plate,  F,  levelled 
roughly  on  blocking  pieces,  G,  or  other  convenient  sup- 
ports, the  loam  board,  D,  notched  out  to  clear  the  boss 
of  the  strap,  and  bolted  thereto.  The  breadth  of  the 
sides  of  the  bar  A  is  definite,  being  usually  If  in.,  2  in., 
2-J-  in.,  or  2^  in.,  so  that  the  radius  of  the  board  1.)  is 
less  than  the  radius  of  the  casting  by  an  amount  equal 
to  H,  the  radius  of  the  bar.  It  is  easy  to  see  the  coin- 
cidence of  the  board  with  the  outside  of  the  casting  by 
comparing  Figs.  158,  159,  the  only  point  of  difference 
being  the  strip,  I,  which  is  screwed  on  temporarily  to  make 
a  parting  joint,  J,  for  convenience,  and  the  step  or  check, 
K,  which  makes  the  top  or  cope  joint.  The  edge  of  the 
board  is  chamfered,  as  shown  at  L,  to  avoid  dragging  up 
and  tearing  out  of  the  loam.  It  is  evident  that  loam 
boards  should  be  truly  level  in  order  to  ensure  the  striking 
of  a  level  mould.  Hence  the  top  edge  should,  in  shallow 
moulds,  be  planed  square  with  the  end  which  abuts  against 
the  bar,  and  a  level  tried  upon  it,  as  shown  at  Z. 


PLAN. 


FIG.  159. — LOAM  MOULDING. 


238  PRACTICAL  IRON  FOUNDING 

When  moulds  are  deep,  the  bar  is  apt  to  sag  at  the  top, 
and  to  cause  the  diameter  to  alter.  For  this  reason,  and 
partly  also  to  check  any  error  in  the  cutting  of  the 
board,  diameter  strips  and  calipers  are  used  for  measure- 
ment of  the  mould.  Fig.  160  shows  the  strip  used  for 
testing  the  interior  of  a  mould,  being  made  to  clip 
the  bar;  and  Fig.  161  the  wooden  calipers  for  the  ex- 
terior. Their  purpose  is  so  obvious  that  they  require  no 
explanation. 

A  thin  coating  of  stiff  loam  is  first  spread  over  plate  F, 
Fig.  159,  and  upon  this  the  bricks,  M,  M,  are  bedded. 
The  bricking  up  is  a  vital  matter,  since  the  bricks  must 


FIG.  160. — DIAMETER  FIG.  161. — WOODEN 

STRIP.  CALIPERS. 

bind  one  another  by  being  made  to  break  joint,  just  as  in 
masonry.  Since  moulds  are  irregular,  and  bricks  are 
pretty  uniform  in  size,  the  value  of  the  broken  bricks 
from  previous  moulds  is  apparent.  These  should  be  util- 
ized as  much  as  possible  instead  of  breaking  new  bricks. 
It  is  not  possible  nor  necessary  to  maintain  such  regu- 
larity as  in  masonry — the  appearance  of  a  bricked  up 
mould  is  rather  that  of  Fig.  159  (plan).  In  building  up 
cylindrical  work  the  general  rule  is  to  keep  the  broken 
bricks  next  the  mould  face,  and  the  whole  bricks  as  a 
backing.  The  broken  bricks  conduce  to  better  venting 
than  the  whole  ones  would  do. 

When  a  mould  is  over  18  in.  or  24  in.  in  depth,  a  cast 


LOAM  WORK  239 

iron  ring  is  built  in  at  about  every  six  courses,  to  assist 
in  binding  the  bricks  together. 

The  joints  of  the  bricks  are  not  only  wide  apart,  but 
large  quantities  of  fine  cinders  are  interspersed  with  the 
loam  in  the  joints.  These  are  introduced  for  the  purpose 
of  venting,  which  is  a  better  and  more  certain  method 
than  venting  with  the  wire,  though  the  wire  is  sometimes 
used  in  some  sections  where  the  loam  happens  to  be 
massed  in  quantity  in  a  mould.  There  must  be  sufficient 
coarse  loam  intermixed  with  the  ashes  to  bind  the  bricks 
together.  The  layers  of  brick  M'  and  M"  are  then  built 
up  in  like  fashion,  with  loam  and  ashes  intermixed.  A 
space  of  about  1  in.  is  left  between  the  bricks  and  the 
edge  of  the  board,  and  about  |  in.  of  this  is  daubed  well 
over  with  stiff  coarse  loam — coarse  loam  because  it 
affords  a  better  vent  to  the  gases  and  air,  than  finer  and 
therefore  closer  loam  would  do.  The  work  is  then  left 
standing  for  a  few  hours  in  order  that  the  loam  may  stiffen. 
Afterwards  the  final  coat  of  loam,  passed  through  a  fine 
sieve,  is  struck  on,  and  finished  by  the  edge  of  the  board. 
Several  sweepings  around  of  the  board  are  necessary  to 
impart  the  final  smoothness  to  the  surface;  then  the 
mould  is  put  into  the  stove  to  be  dried.  At  this  stage 
therefore  the  mould  is  completed  up  to  joint  J,  which 
coincides  with  the  lower  face  of  the  flange  B  in  Fig.  158, 
the  mould  being  made,  as  just  now  remarked,  to  pour 
the  casting  upside  down. 

Fig.  162  illustrates  the  next  stage.  A  cast  iron  plate, 
G,  is  made,  a  thin  coating  of  loam  swept  over  one  face 
and  dried.  The  flange  space  N,  already  struck,  as  in 
Fig.  159,  is  filled  up  temporarily  with  moulding  sand  level 
with  the  joint  J,  and  then  the  loarned  face  of  G  is  turned 
over  thereon,  parting  sand  intervening.  The  strip  /,  in 


240  PRACTICAL  IRON  FOUNDING 

Fig.  159,  is  unscrewed  from  the  board,  and  the  second 
stage  of  bricking  up  is  done  on  plate  G,  Fig.  162. 

Sometimes  ring  plates  are  used  similar  to  G,  merely 
for  the  convenience  of  parting  a  mould  which  is  too  deep 
to  go  into  the  drying  stove  entire.  The  upper  portion  of 
the  mould  is  then  lifted  off  on  its  ring  before  being  put 
into  the  stove,  and  is  replaced  after  it  has  been  dried. 
The  ring  is  like  G,  but  its  function  is  different,  G  in 
Fig.  162  being  necessary  because  the  under  face  of  flange 
N  could  not  be  struck  at  the  same  time  as  the  lower  portion 
of  the  mould  in  Fig.  159,  without  much  difficulty,  due  to 
falling  down  of  the  loam. 

There  are  four  ribs,  C,  Fig.  158,  cast  between  the 
flanges.  These  are  made  by  imbedding  four  pattern  ribs, 
0,  Fig.  162,  in  corresponding  positions,  and  spaces  are 
cast  out  of  the  plate,  G,  to  receive  these.  Whenever  ribs, 
facings,  brackets,  flanges,  which  cannot  be  struck,  occur 
in  loam  moulds,  patterns  of  these  have  to  be  made  as  in 
ordinary  work.  In  some  cases  where  the  work  is  intricate 
this  becomes  a  source  of  trouble  to  the  moulder.  In  the 
first  place  it  is  not  easy  to  set  sectional  portions  of  wood 
very  accurately  in  yielding  loam.  Then  the  wood  remains 
in  the  loam  for  several  hours,  more  often  for  days,  and 
is  liable,  by  its  distortion,  to  produce  inaccuracy.  Again, 
it  is  not  so  easy  to  secure  a  homogeneous  face  of  loam 
by  building  bricks  against  wood  as  it  is  by  striking  loam 
upon  bricks.  The  wood  has  to  remain  in  the  mould 
either  until  the  loam  has  become  stiffened  or  until  after 
it  has  been  baked  in  the  stove.  In  either  case  the  with- 
drawal of  the  wood  tends  to  damage  the  mould — more 
when  it  is  baked,  because  the  loam  then  absorbs  some  of 
the  oily  matter  from  the  wood.  This  makes  mending  up 
of  the  faces  troublesome,  the  oily  surface  not  taking 


PLATE  X 


See  p.  295 

FIG.  203.— THE  FARWELL  HAND  PORTABLE  MACHINE 


[Facing  p.  240 


See  p.  297 

FIG.  204. FARWELL  UNIVERSAL  MACHINE 


PLAN. 


Fro.  162.— LOAM  MOULDING. 


242  PRACTICAL  IRON  FOUNDING 

kindly  to  the  wet  loam  used  in  mending.  In  such  cases 
the  surfaces  should  be  scraped  before  being  mended.  It 
is  the  usual  practice  to  oil  the  surfaces  of  the  woodwork 
imbedded  in  loam;  but  this  only  partially  assists  the 
stripping.  The  ribs  in  the  illustration,  though  suggesting 
these  remarks,  are  so  plain  that  they  would  cause  no 
trouble.  It  is  in  work  of  a  more  intricate  character  that 
trouble  occurs. 

At  P  in  Fig.  162  are  bricks  which  are  made  of  loam, 
moulded  into  the  shape  of  bricks,  and  dried.  These 
occupy  the  spaces  between  the  ribs.  Loam  bricks,  as  they 
are  termed,  are  frequently  used  in  moulds  of  this  char- 
acter wherever  there  are  narrow  spaces  between  flanges, 
or  brackets,  or  ribs.  One  reason  is,  that  if  the  shrinkage 
of  the  casting  takes  place  against  hard  unyielding  bricks, 
the  iron  is  liable  to  fracture.  If  loam  bricks  are  used, 
they  crush  and  yield  before  the  shrinking  metal.  They 
have,  moreover,  the  additional  advantage  of  forming  a 
good  medium  for  venting,  and  this  is  an  important 
point.  In  intricate  portions  of  moulds  it  is  safer  to  use 
loam  bricks  and  an  extra  thickness  of  loam  vented  with 
the  wire,  than  to  bring  the  common  bricks  very  near  the 
surface.  A  thin  body  of  loam  against  common  bricks  is 
always  liable  to  become  detached,  and  to  cause  scabbing 
by  reason  of  the  bubbling  of  the  metal  thereon. 

Outside  the  loam  bricks  JP,  a  layer  of  common  bricks, 
Qt  is  built,  and  over  this  again  another  similar  course 
Q'.  The  thickness  of  loam  is  daubed  and  swept  over 
the  faces  of  the  bricks  according  to  the  profile  of  the 
board  D. 

The  cope,  and  the  central  core  yet  remain.  A  plate, 
R,  Fig.  163,  is  cast,  studded  over  with  prods  to  hold  the 
loam  which  is  swept  over  its  face,  as  shown — the  check  K 


FIG.  163. — LOAM  MOULDING. 


244  PRACTICAL  IRON  FOUNDING 

being  formed  to  correspond  with  the  reverse  check  K  in 
Fig.  162 — and  allowed  to  set  firmly.  While  it  is  setting, 
the  plate  H  is  partly  loamed  up  on  separate  blocking. 
The  future  position  of  this  plate  is  seen  in  Fig.  163;  the 
arms  S,  shown  at  7),  in  Fig.  158,  are  laid  in  due  posi- 
tion, and  stiff  loam  is  daubed  around  them,  so  that  when 
this  sets  the  arms  are  kept  pretty  rigidly  in  place. 
While  the  loam  is  setting,  the  work  on  plate  H  is  con- 
tinued; courses  of  bricks,  U,  U,  are  built  upon  the  bed 
which  has  been  already  struck  with  the  board,  the  joints 
being  vented  with  cinders,  or  with  the  wire.  Coarse  loam 
is  daubed  around  the  outside,  and  also  on  the  top  of  the 
uppermost  layer.  Then  the  plate,  H,  is  laid  upon  the  top 
layer  of  loam,  Fig.  163.  The  irons,  V,  are  for  the  purpose 
of  wedging  up  and  securing  the  core  and  cope  when 
finally  in  place.  H,  bedding  firmly  on  the  loam,  the 
spaces  between  the  ribs  are  filled  in  with  loam  bricks, 
U',  and  these,  with  the  deep  prods  cast  on  the  plate, 
together  with  the  stiff  loam  daubed  between  them  all, 
form,  when  dried,  a  solid  mass  which  can  be  turned  over 
with  perfect  safety  for  closing  the  mould.  The  block  W, 
which  gives  the  metal  around  the  termination  of  the 
bottom  steam  passage  of  the  cylinder,  E,  in  Fig.  158,  is 
bedded  in,  and  the  whole  surface  is  lastly  swept  up  and 
finished  with  fine  loam,  SS,  and  the  whole  dried  bodily 
in  the  stove. 

The  turning  over  of  a  body  of  bricks,  etc.,  like  that  in 
Fig.  163,  is  only  done  in  cases  where  the  mass  is  not  ex- 
cessive. In  the  example  which  we  have  selected  there  is  no 
difficulty  or  risk  involved  in  turning  over.  But  in  some 
heavy  work  it  would  be  necessary  to  make  a  reverse 
mould,  and  to  daub  the  loam  upon  that,  standing  thus  in 
the  position  in  which  it  is  to  stand  when  finished.  Also 


PLAN. 


FIG.  164. — LOAM  MOULDING. 


246  PRACTICAL  IRON  FOUNDING 

where  a  reverse  mould  would  not  be  suitable,  the  prin- 
ciple adopted  in  Fig.  162  is  often  employed,  that,  namely, 
of  striking  one  portion  of  a  mould  upon  another,  using  a 
parting  ring,  G,  and  parting  sand. 

Loam,  like  dry  sand,  must  be  thoroughly  dried,  so 
that  no  steam  issues  therefrom.  When  dried,  the  mould 
is  blackened  with  wet  blacking,  and,  as  soon  as  this  is 
dry,  the  mould  should  be  finally  closed  for  casting.  The 
checks  7i,  in  Figs.  162, 168,  furnish  an  accurate  means  of 
joining  the  top  and  bottom  portions  of  the  mould.  Holes 
cut  at  Y,  Fig.  164,  enable  the  moulder  to  see  whether  the 
coincidence  of  the  joints  is  correct,  and  if  not,  where  to 
file  away  the  loam. 

Fig.  164  shows  the  mould  closed  in  readiness  to  be  placed 
in  the  casting  pit.  Similar  reference  letters  will  assist  in 
the  recognition  of  parts  identical  with  those  in  the  pre- 
vious figures,  and  the  outline  of  the  mould  is  also  dotted. 
The  eyes  V  receive  the  rods  V,  which  are  secured  with 
the  wedges  V",  thus  securing  the  central  core  and  cope 
in  place.  The  top  and  bottom  plates,  R,  F,  are  clamped 
together  with  the  clamps  Z',  Z',  which  are  wedged. 
Eunner  pins  are  inserted  at  x,  to  keep  the  ingates  clear 
during  the  time  of  closing,  and  of  placing  in  the  pit. 
Then  the  pouring  basin,  Fig.  164,  X,  and  riser  cups,  X',  are 
made,  and  all  is  ready  for  pouring.  In  cases  where  the 
mould  is  of  considerable  size  the  practice  is  to  fill  the 
central  space  of  a  bricked  up  core,  as  SS,  in  Fig.  163, 
with  cinders,  previous  to  casting.  If  this  precaution  were 
not  taken,  the  air  filling  the  vacant  space  would  rush 
out  with  explosive  violence  on  the  pouring  of  the  metal. 
The  cinders  form  a  natural  vent,  to  the  exclusion  of 
excess  of  air. 

Feeding  is  performed  at  the  riser  cups  X',  and  at  the 


LOAM  WORK 


247 


pouring  basin  X.  Vents  are  brought  away  all  over  the 
surface  of  the  cope,  and  also  from  the  bottom,  the  latter 
through  diagonal  vent  pipes. 

The  mould  is  sunk  into  the  floor,  or  pit,  and  sand 
rammed  around  it,  in  order  to  prevent  risk  of  the  liquid 


FIG.  165. — SOAP  BOILING  PAN. 

pressure  from  forcing  out  the  bricks  composing  the 
mould.  For  large  work,  therefore,  special  pits  are  built 
in  the  foundry  floor.  These,  when  permanent,  are  built 
up  with  cast  iron  plates,  or  rings.  They  are  made  of 


FIG.  166. — FIRST  STAGE  IN  MAKING  MOULD. 

depth  and  diameter  most  suitable  for  the  special  require- 
ments of  the  foundry. 

Fig.  165  illustrates  a  soap  boiling  pan,  and  Figs.  166 
to  170  show  how  the  loam  mould  was  made.  It  was  cast 
bottom  upwards.  The  hole  in  the  bottom  receives  a  dished 
or  cup-shaped  vessel  (not  shown)  surrounded  by  a  flange 


248 


PRACTICAL  IRON  FOUNDING 


which  was  bolted  to  the  inner  face  of  the  flange  on  the 
casting,  so  forming  the  bottom  of  the  pan. 

First  the  outside  was  swept  up,  and  then  removed  to 
allow  of  rigging  up  the  board  for  sweeping  the  inner  or 
cored  portion.  Fig.  166  shows  the  first  stage  in  the  work. 
Plate  A,  about  3  in.  thick,  is  cast  with  prods  and  sup- 
ported on  wood  blocking,  and  then  a  level  loam  joint 
face  a  is  swept  on  it  with  the  board  B  which  is  bolted  to 
a  strap  set  on  the  central  striking  bar  in  the  usual  way. 


FIG.  167. — MOULD  BODY  SWEPT  UP. 

The  loamed  joint  a  is  dried,  and  then  an  outer  ring  of 
cast-iron,  D,  Fig.  167,  which  is  first  loamed  over  on  the 
under  side,  dried  and  turned  over — is  jointed  to  it,  and 
on  this  ring  the  courses  of  bricks,  E,  Fig.  167,  are  built  up 
and  a  coat  of  loam  swept  on  the  interior  by  the  board  F, 
which  is  made  as  shown,  and  attached  to  the  central  bar 
with  two  straps.  The  board  has  a  strip  b  screwed  on  it  to 
prevent  the  loam  from  falling  from  the  overhanging 
body  on  to  the  level  bed  which  has  been  previously 
swept  over  the  bottom  plate. 

When  this  coat  has  set  sufficiently,  the  ring  D  with 


LOAM  WORK 


249 


its  bricked  mould  is  lifted  away,  hung  by  its  lugs  in  the 
crane  slings,  and  is  put  in  the  oven  to  dry  while  the 
inner  portion  or  core  is  being  swept  up.  Fig.  168  shows 
the  bricking  up  on  the  plate  G,  and  the  sweeping  board 
H  rigged  up.  To  allow  the  metal  to  shrink  in  cooling 
without  risk  of  fracture,  four  tiers  of  loarn  bricks  are 
built  up  between  the  common  bricks,  90°  apart.  These 
are  broken  out  with  a  bar  soon  after  the  casting  has  set, 


rr— 


FIG.  168. — CORE  SWEPT  UP. 

and  so  leave  the  hard  bricks  free  to  yield  before  the 
shrinking  casting  without  risk  of  fracture  of  the  latter. 
The  overhang  of  the  board  is  stiffened,  and  prevented 
from  wobbling  and  dragging  by  means  of  an  iron  strap  J, 
attached  as  seen  in  Fig.  168.  When  finished,  the  bottom 
plate  with  its  core  is  put  bodily  into  the  stove  and 
dried,  and  afterwards  the  outside  mould  is  put  in  posi- 
tion finally. 

Figs.  169  and  170  show  the  top  of  the  mould,  which  is 


250 


PRACTICAL  IRON  FOUNDING 


a  plain  cope  only.  It  is  formed  of  a  plate  K  exactly  like 
the  bottom  plate  A  in  Fig.  166,  with  prods,  loamed,  and 
swept  level  with  the  board  73  in  Fig.  166  to  make  the 
joint  face  c  in  Fig.  169.  Six  holes  are  cast  in  the  plate 
through  which  the  ingates  d  pass,  the  pan  being  poured 
thus.  A  pouring  basin  in  sand  is  rammed  on  top,  through 
which  the  runners  are  filled.  This  is  conveniently  formed 
in  the  manner  shown  in  Figs.  169  and  170.  Two  cast  iron 
pit  rings  e,  e,  are  selected  of  any  approximate  diameters 
suitable,  and  laid  concentrically  on  the  top  plate,  and 
the  annular  pouring  basin  is  made  up  between  them  as 


FIG.  169. — MOULD  COMPLETED. 

seen  in  section  in  Fig.  169,  half-a-dozen  runner  sticks 
being  set  in,  while  the  basin  is  being  moulded  by  the 
rammer,  and  smoothed  by  the  hands.  This  is  preferable 
to  allowing  the  metal  to  enter  by  one  or  by  two  ingates 
only  at  opposite  sides,  as  it  would  have  a  tendency  to 
chill  in  filling  the  mould.  Entering  hot  at  so  many 
different  places  there  is  no  risk  of  cold  shuts  or  of  im- 
perfect edges. 

It  is  better  to  conduct  the  metal  through  an  exterior 
basin  L  than  to  pour  it  directly  into  the  annular  channel, 
which  if  attempted  would  probably  result  in  the  falling 
of  driblets  of  metal  into  the  mould,  to  become  chilled 


LOAM  WORK  251 

before  the  ladle  could  be  properly  adjusted  to  pour  the 
main  volume.  Pouring  the  metal  into  the  basin  I/,  exact 
adjustment  of  the  ladle  is  effected,  while  the  basin  slowly 
fills,  after  which  a  steady  volume  being  emptied  into  it, 
overflows  into  the  annular  basin,  and  through  the  in- 
gates  d.  The  basin  L  is  made  within  any  moulding  box 
part /of  suitable  size,  prevented  from  shifting  by  an  en- 


FIG.  170. — PLAN  OF  MOULD. 

closing  body  of  sand.  Opposite  it  is  the  flow-off  basin  M. 
This  is  made  of  sand  alone,  supported  by  ramming  in  a 
few  wetted  bricks. 

The  top  and  bottom  plates  K  and  A  are  secured  during 
pouring  by  means  of  iron  clamps  N,  seen  in  Fig.  170 
and  to  the  right  of  Fig.  169,  held  fast  with  wedges.  For 
casting,  the  mould  is  placed  in  a  convenient  pit  0,  Figs. 
169  and  170.  The  interior  of  the  core  has  been  filled  with 
cinders  to  receive  the  gases  quietly,  and  prevent  explosion. 


252 


PRACTICAL  IRON  FOUNDING 


These  are  conducted  away  through  a  central  pipe.  The 
outside  is  rammed  around  with  sand  to  prevent  displace- 
ment of  the  bricks  by  the  liquid  pressure.  The  outer  air 
will  come  up  through  the  sand  which  will  be  well  vented 
vertically  with  the  vent  wire. 

Loam  patterns. — These  constitute  another  type  of  this 
branch  of  work,  having  a  single  point  only  in  common 


FIG.  171. — HYDRAULIC  CYLINDER. 

with  loam  moulds — the  material  in  which  they  are  made. 
They  are  employed  when  the  work  is  of  a  medium  size — 
too  small  to  be  struck  upon  bricks,  yet  so  large  as  to  in- 
volve costly  outlay  for  patterns  in  wood.  They  are  struck 
up  pretty  much  like  cores  on  core  bars,  except  that  no 
venting  is  required,  and  the  surface  is  protected  and 
rendered  hard  with  a  coating  of  tar.  In  many  cases, 
however,  as  when  one  casting  only  is  required,  the  core 


LOAM  WORK  253 

is  struck  first  and  vented  in  the  usual  way,  and  then  a 
body  of  loani,  representing  the  thickness  of  metal  in  the 
casting,  is  struck  thereon,  a  coat  of  black  wash  interven- 
ing. The  mould  is  then  made  and  the  thickness  re- 
moved, the  black  wash  acting  as  a  parting,  allowing  of 
the  ready  peeling  off  of  the  thickness,  and  the  core  is 
placed  in  its  mould.  The  boards  used  for  striking  are 
similar  to  those  used  for  striking  cores. 

The  figures  illustrate  the  manner  in  which  the  pattern 
for  one  of  the  lifting  cylinders  of  a  hydraulic  crane  can 
be  made.  They  afford  a  good  example  of  the  economy  of 
patternmaking  in  loam  when  the  cylinder  is  large  in 
diameter  and  of  considerable  length.  In  this  case  it  is 
12  ft.  long  by  18  in.  diameter. 

Fig.  171  shows  the  casting.  The  bracket  for  the  bottom 
chain  pulleys  is  bolted  to  the  flange  A,  while  the  end  B 
forms  the  stuffing  box  for  the  ram;  and  by  means  of 
the  facing  strips  shown  at  the  sides  three  cylinders  are 
bolted  to  each  other  on  one  side,  and  to  the  cheeks 
which  form  the  side  members  of  the  crane  post  on  the 
other. 

This  is  riot  a  loam  pattern  pure  and  simple,  but  one 
of  a  composite  character,  being  partly  of  loam  and  partly 
of  wood.  It  is  clear  that  the  more  intricate  and  delicate 
portions  of  patterns  cannot  be  formed  so  economically 
or  strongly  in  loam  as  in  wood,  hence  there  are  few 
patterns  which  are  constructed  entirely  of  loam,  except 
those  of  the  very  simplest  and  most  symmetrical  types. 
Generally,  as  in  this  instance,  the  main  body  is  of  loam, 
and  the  small  attachments  are  of  wood. 

The  loam  body  is  made  as  follows :  A  common  core-bar 
(Fig.  172,  A)  is  used,  and  hay  bands  are  wrapped  around 
it,  sufficient  in  number  to  make  up  the  size  of  the  body 


254 


PRACTICAL  IRON  FOUNDING 


required.  There  is  no  need  to  use  plates  in  a  case  like 
this  (such  as  are  rigged  up  when  sweeping  cores),  be- 
cause a  bar  sufficiently  rigid  in  itself  can  be  selected 
without  further  aid  from  plates.  A  plate  must  be  used 
at  each  end,  in  order  to  afford  support  to  the  loam  there. 
Hay  bands  and  loam  alone  form  the  pattern  body.  The 
bands,  especially  the  first  layer  or  two,  must  be  left 
rather  open,  and  the  loam  worked  into  the  openings, 
going  down  to  the  corebar,  and  becoming  interlocked 
and  held  fast  among  the  bands,  so  that  there  will  be  no 
risk  of  its  flaking  off  afterwards. 

As  in  coremaking,  the  first  application  must  be  allowed 


Fm.  172. — LOAM  PATTERN  OF  CYLINDER. 

to  become  partially  set  before  the  final  coat  is  put  on, 
and  the  last  coat  of  all  must  be  thinner  and  finer  than 
that  used  for  the  main  body.  Fig.  172  shows  the  pattern 
at  this  stage,  A  being  the  bar,  B  the  body,  C  the  head 
metal,  and  I),  D  the  prints. 

The  mode  of  attachment  of  the  wood  fittings  to  a  loam 
pattern  is  governed  by  the  facilities  which  are  afforded 
by  the  shape  of  the  pattern  itself.  Loose  fittings  are  apt 
to  become  rammed  out  of  truth,  since  the  same  means 
are  not  available  for  the  attachment  of  wood  to  loam  as 
for  wood  to  wood.  Screws  cannot  be  inserted,  and  nails, 
though  used,  afford  but  a  flimsy  fastening  in  the  loam, 
and  their  principal  use  is  to  steady  rather  than  to 


LOAM  WORK 


255 


secure.  Square-shouldered  portions  (Fig.  172,  a)  afford 
ample  means  of  security  when  wood  is  fitted  to  loam, 
because  where  such  a  deep  shoulder  exists  it  gives  a 
good  bedding  for  a  wood  fitting  without  any  fastening, 
and  the  latter  is  readily  held  against  the  shoulder  by 
pressure  of  the  hand  while  the  first  portions  of  sand  are 
being  rammed  around  it.  A  recess  like  that  at  b  is  more 
secure  still.  Often,  however,  there  need  be  no  better  fit- 
ing  than  thatwhich  a  butt  joint  affords.  Then  the  wood 
portion  may  be  either  set  and  kept  in  place  by  careful 
measurement,  with  rule,  straightedge,  or  square;  or  in 


FIG.  173. 


FIG.  174. 


WOOD  FITTINGS. 


some  cases  slight  assistance  can  be  derived  from  nails 
passing  deeply  into  the  loam,  either  through  the  wood 
or  alongside  of  it. 

Fig.  173  shows  the  mode  of  attachment  of  the  bottom 
flange  A  in  Fig.  171  against  the  shoulder  a  in  Fig.  172 
one-half  the  flange  only  being  in  place,  a  face  view  of  the 
same  half  being  given  to  the  left.  The  flange  is  simply 
held  against  the  square  shoulder  until  sufficient  sand  has 
been  tucked  around  to  keep  it  in  position.  The  facings 
and  core  prints  are  self-explanatory. 

Figs.  174  to  176  illustrate  the  fittings  which  go  at  the 
head  B  in  Fig.  171.  The  flange  B  forms — along  with  the 
flanges  C,  C  by  which  the  cylinders  are  bolted  together 


256 


PRACTICAL  IRON  FOUNDING 


and  to  the  post,  the  ribs  d,  d  stiffening  these — together 
with  sundry  prints  and  planing  strips — a  single  pattern 
piece  which  drops  over  the  portion  marked  b,  E,  in  Fig. 
172;  the  flange B  in  Figs.  174  and  175  dropping  into  It  in 
Fig.  172,  and  the  flat  E  in  Fig.  172  being  filed  to  allow 
the  width  Z)  in  Fig.  176  to  embrace  it.  In  the  absence  of 
the  flats,  the  facings  (7,  C  in  Fig.  176  would  have  to  be 
cut  away  to  fit  the  circular  body  of  loam,  which  would 
not  be  so  conveniently  done. 

The  prints  E,  E  are  merely  for  lightening  recesses, 


t       E 

FIG.  175.  FIG.  176. 

WOOD  FITTINGS. 

and  the  pocket  or  drop  prints  <>,  <>  are  for  the  bolt  holes. 
This  entire  piece  is  retained  in  the  groove  b  in  Fig.  172, 
and  therefore  requires  no  assistance  or  support  when 
ramming. 

The  appearance  of  the  completed  pattern  is  seen  in 
Fig.  177,  the  view  being  taken  looking  down  on  it  from 
above,  so  that  the  joints  in  the  fittings  do  not  show. 

The  economy  of  making  large  loam  patterns  is  well 
illustrated  in  this  example,  both  in  regard  to  time  and 
material  saved.  Hay  bands  and  loam  do  not  cost  so 
much  as  wood,  nor  does  the  striking  up  occupy  so  much 
time  as  the  turning  of  timber.  But  the  latter  is  never- 


LOAM  WORK 


257 


theless  cheaper  when  there  are  many  castings  required, 
even  though  the  pattern  should  be  large.  The  question 
is  merely  one  of  relative  cost.  In  this  case  the  pattern 
was  of  large  dimensions,  and  only  three  castings  were 
required.  The  storage  room  necessary  for  large  wood 
patterns  also  has  to  be  considered  when  deciding  between 
timber  and  loam. 

Loam  patterns  which  are  swept  up  are  necessarily  un- 
jointed,  which  is  a  slight  disadvantage,  because  they  can- 
not be  laid  upon  a  bottom  board,  neither  have  they  a  flat 
central  face  from  which  to  square  up  and  mark  off  the 


FIG.  177. — PATTERN  COMPLETED. 

positions  of  their  attachments.  Hence  centre  lines  have 
to  be  obtained  by  rule,  compasses,  and  straightedge,  and 
most  squaring  up  must  be  done  from  the  outer  surface 
of  the  body  or  by  geometrical  means. 

When  moulding  a  solid  pattern  of  this  kind  it  is  bedded 
in  the  sand  of  the  floor  and  covered  with  a  top  part;  or 
in  a  complete  flask.  If  in  the  latter,  the  box  part  which 
is  to  come  in  the  bottom  is  rammed  over  it.  Then  it  is 
turned  over  and  the  top  rammed  on.  Or,  if  cast  in  the 
floor,  it  will  be  bedded-in  like  any  other  pattern,  and  the 
top  part  rammed.  In  either  case  a  longitudinal  centre 
line  is  marked  deeply  down  each  side  as  a  guide  to  the 
moulder  for  marking  his  parting  joint  by,  and  the  edges 


258  PRACTICAL  IRON  FOUNDING 

of  the  flanges  must  be  tried  with  parallel  or  winding 
strips  before  the  ramming  is  completed,  and  if  out  of 
truth  with  each  other  must  be  corrected. 

Cylinders  of  this  character  are  cast  on  end  to  ensure 
closeness  of  metal,  since  they  have  to  stand  very  high 
pressures.  The  metal  is  poured  at  the  top,  and  falls  the 
entire  depth;  and  though  poured  as  "  dead  "  as  it  is  safe 
to  run  it,  and  the  mould  made  of  dry  sand,  the  iron  will 
cut  up  and  burn  into  the  bottom  portion  of  the  mould. 
The  driving  in  of  a  number  of  flat-headed  nails  in  close 
contiguity  (Fig.  178),  just  level  with  the  surface  of  the 


FIG.  178. — NAILS  IN         FIG.  179.— STRICKLING. 
BOTTOM  OF  MOULD. 

sand,  and  well  oiling  them,  will  prevent  this  cutting  up 
and  burning,  by  giving  the  metal  a  hard  bed  to  fall  on. 

Loam  patterns  of  irregular  outline  are  worked  up  with 
strickles,  guidance  to  which  is  afforded  by  means  of  guide 
irons,  or  by  striking  plates.  The  principle  is  simple. 
Fig.  179  shows  a  strickle  of  half  a  pipe,  working  by  means 
of  a  check  against  a  guide  iron,  A,  which  is  curved  longi- 
tudinally to  correspond  with  the  required  outline  of  the 
pipe,  Fig.  180.  The  guide  iron  remains  in  the  same  posi- 
tion for  both  core  and  pattern,  the  concentricity  of  core 
and  pattern  being  assured  by  the  method  of  cutting  the 
checks  upon  each  strickle,  the  distance,  B,  being  less  in 
the  pattern  strickle  than  in  the  core  strickle  by  an  amount 
equal  to  the  thickness  of  metal  in  the  pipe  to  be  cast. 
In  making  the  core,  the  vents  have  to  be  carried  from  the 


LOAM  WORK 


259 


outside  to  the  central  portion,  and  away  at  the  ends. 
Cores  are  differently  made  according  to  their  diameters. 
A  small  core  is  stiffened  only  with  a  couple  of  irons.  A 
large  one  has  a  grid  with  prods.  In  a  small  one,  the 
central  vent  is  simply  cut  with  a  trowel  in  the  joint  after 
each  half  has  been  dried  and  turned  over,  while  in  a  large 
one  the  central  vent  is  formed  by  daubing  the  loam  over  a 
central  body  of  green  sand,  first  made  roughly  semi- 
circular with  the  hands. 

Fig.  180  shows  the  various  stages  in  making  a  common 


FIG.  180. — LOAM  PATTERN. 


socket  bend  in  loam.  Assume,  for 
the  sake  of  definite  dimensions,  that 
it  is  a  12  in.  bend  with  £  in.  metal. 
Then  the  first  thing  is  to  lay  down  a  guide  iron,  //,  which 
may  be  ^  in.  away  from  the  outside,  and  of  course  1  in. 
away  from  the  core.  Then  the  core  strickle  will  have  a 
1  in.  check,  B,  Fig.  179,  and  the  pattern  strickle  a  -J  in. 
check.  Weights  will  steady  the  guide  iron.  First  a  body 
of  green  sand,  C,  is  made  roughly  semicircular  with  the 
hands.  Then  wet  loam  is  daubed  upon  this  and  brought 
up  to  within  about  -|  in.  of  the  strickle  as  shown,  Figs. 
179, 180,  D;  a  cast  iron  grid,  E,  being  bedded  in  the  loam 
at  the  same  time.  While  the  loam  is  yet  plastic,  a  number 


260  PRACTICAL  IRON  FOUNDING 

of  -f  in.  or  J  in.  holes  are  pierced  through  it,  reaching  to 
the  interior.  These  are  the  main  vents.  When  this  coat 
of  loam  has  partly  set,  the  finishing  fine  coat  is  laid  on 
and  swept  round  with  the  strickle,  as  shown  at  F.  It  is 
evident  that  two  such  halves  put  together  joint  to  joint 
and  cemented,  will  form  a  properly  stiffened  and  vented 
core. 

The  enlargement  in  diameter  at  the  socketed  end  is 
usually  made  by  striking  up  a  ring  of  loam  and  thread- 
ing it  upon  the  core,  its  vents  being  brought  into  the 
main  core  vents. 

The  next  stage,  if  one  casting  only  is  required,  is  the 
striking  of  the  pattern  thickness  upon  the  core.  Nothing 
is  moved,  but  the  core  is  coated  with  black  wash,  and 
the  loam  struck  thereon  with  the  pattern  strickle,  as  at 
77.  This  also  is  dried. 

The  socket  is  variously  made.  Sometimes  the  thick- 
ness, forming  the  socket  core,  is  not  put  on  until  after 
the  pipe  has  been  moulded.  The  socket  body  is  struck 
and  threaded  directly  on  the  plain  core  as  at  G,  or  a 
standard  wooden  or  iron  socket  pattern  is  slipped  over. 
Sometimes  the  socket  is  struck  up  on  its  own  core, 
either  by  means  of  a  guide  ring,  Fig.  180,  /,  which 
forms  a  portion  of  the  pattern,  and  strickle,  J,  working 
thereon  transversely,  or  the  two  separate  diameters, 
7,  K,  are  struck  with  two  separate  strickles  working  from 
the  guide  iron,  and  the  curves  by  which  they  merge  into 
one  another  are  rubbed  by  hand  with  rasps  and  glass- 
paper. 

When  a  pattern  thickness  is  struck  upon  a  core  as  in 
this  case,  it  is  usually  necessary  to  secure  the  thick- 
ness firmly,  during  moulding  and  handling  about,  with 
flat-headed  plasterers'  or  chaplet  nails;  without  this 


LOAM  WORK  261 

precaution  the  thickness  is  apt  to  peel  off  at  the  black 
wash  joint. 

When  a  pattern  is  struck,  the  diameters  of  which  vary 
at  every  position,  no  single  templet  will  shape  it.  Then 
strickles  are  made  to  the  extreme  diameters,  and  if  the 
pattern  is  of  awkward  shape,  strickles  also  for  certain 
intermediate  positions,  and  the  loam  is  rubbed  between 
these  positions  with  files  or  rasps,  the  eye  being  the  arbiter, 
with  or  without  the  assistance  of  sectional  templets.  In 
a  reducing  bend  three  such  positions  might  be  taken, 
one  at  each  end,  and  one  at  the  centre,  and  two  guide 
irons  would  properly  be  used.  The  three  strickles  rest- 
ing against  the  guide  irons  would  give  the  semicircular 
outline  at  each  position,  and  the  longitudinal  outline  of 
the  guide  irons  would  give  the  curves  by  which  the 
joint  edges  of  the  cores  would  be  imparted,  the  strickles 
for  these  being  of  a  sectional  form,  giving  the  edges  only. 

When  the  core  has  been  rubbed  down  to  its  proper 
curves,  the  thickness  is  variously  put  on.  Thus,  strickles 
may  be  used  at  the  ends  and  middle  just  as  in  the  core. 
But  this  leaves  the  eye  to  judge  of  thickness,  which  in 
thin  castings  is  too  risky.  Hence  thickness  pieces  are 
fitted  to  the  core,  being  either  wood  strips,  curved  or 
straight,  gauged  to  thickness,  or  flat-headed  nails  are 
driven  in  by  templet.  These  afford  a  guide  by  which 
the  loam  is  daubed  on  and  strickled  off.  All  these  are 
easily  removed  after  the  pattern  is  moulded  and  the  core 
is  required. 

The  flanges  on  loam  patterns  are  usually  made  in  wood, 
and  they  rest  against  the  shoulders  of  the  loam  \shich 
forms  the  pattern  thickness.  These  shoulders  are  there- 
fore filed  quite  square  after  the  thickness  has  been  dried 
in  the  stove. 


262  PRACTICAL  IRON  FOUNDING 

In  some  loam  patterns  there  is  a  great  deal  of  this 
fitting  of  wooden  parts,  portions  which  cannot  be  made 
in  loam  being  conveniently  made  in  wood.  A  little  knack 
and  some  rough  geometry  is  often  essential  therefore  in 
this  class  of  work.  Centre  lines,  and  lines  at  right  angles, 
which  can  only  be  struck  with  trammels  or  compasses, 
are  often  wanted,  and  their  accurate  laying  down  is 
rendered  all  the  more  difficult,  because  many  loam  pat- 
terns are  unjointed. 


CHAPTEK  XIII 

THE  ELEMENTS  OF  MACHINE  MOULDING 

THE  elements  of  machine  moulding  exist  in  the  use  of 
turn-over  boards,  and  in  plate  moulding,  devices  which 
are  employed  to  a  greater  or  less  extent  in  nearly  all 
shops. 

Turn  over  boards,  joint  boards,  bottom  boards,  as  they 
are  variously  named,  are  employed  to  facilitate  the  making 
of  the  joint  faces  of  moulds.  In  ordinary  work  these  faces 
are  made  by  strickling  and  sleeking  down,  as  noted  on 
pp.  140-2  in  connection  with  Figs.  64-70.  But  when  similar 
work  is  often  repeated  the  joint  faces  are  rammed  directly 
upon  boards,  the  contour  of  the  faces  of  which  corresponds 
with  that  of  the  joint  faces  of  the  sand — flat,  if  required 
flat,  irregular,  sloping,  curved,  etc.,  if  so  required.  In  the 
simplest  mould,  the  flask  which  is  to  become  the  bottom 
or  drag  is  laid  upon  the  bottom  board  over  the  pattern, 
rammed,  lifted  off  with  the  pattern  or  portion  of  the 
pattern  belonging  thereto  enclosed  in  situ,  turned  over, 
and  the  cope  rammed  upon  it.  This  method  is  very 
advantageous  in  two  cases:  first,  when  the  pattern  is  so 
flimsy  that  it  would  probably  become  rammed  out  of 
truth,  or  could  only  be  kept  with  difficulty  from  winding 
during  ramming;  and  second,  when  the  parting  joints 
are  so  uneven,  unsymmetrical,  curved,  sloping,  and  irre- 
gular, that  to  cut  and  sleek  them  with  the  trowel  at  each 
time  of  moulding  would  entail  much  loss  of  time. 

263 


264  PRACTICAL  IRON  FOUNDING 

Plate  moulding  is  an  advance  upon  this  practice.  Using 
turn-over  boards,  the  cope  is  rammed  on  the  drag,  joint 
to  joint,  in  the  positions  which  both  are  to  occupy  finally 
at  the  time  of  casting.  But  in  plate  moulding  the  joint 
faces  are  not  brought  together  at  all  until  the  time  of 
final  closing.  The  pattern  is  divided  into  two  portions, 
one  portion  being  upon  one  side  of  a  plate  of  wood  or 
metal,  the  supplementary  portion  being  upon  the  opposite 
side.  Or  in  many  cases  distinct  plates  are  employed,  each 
carrying  that  portion  of  the  pattern  which  is  the  supple- 
ment of  the  portion  on  the  other  plate.  Cope  and  drag 
being  rammed,  each  on  its  respective  side  of  the  plate, 
or  on  its  separate  plate,  form  when  brought  together  a 
complete  mould,  corresponding  at  the  joints.  Thus,  taking 
an  example,  the  trolly  wheel  shown  in  Figs.  64-67,  p.  141, 
would,  if  moulded  on  a  plate,  be  made  as  in  Fig.  181.  It  is 
clear  that  the  portion  of  the  wheel  on  the  face  B  of  the 
plate  is  supplementary  to  that  on  face  C.  The  faces  B  and 
C  form  the  joint  faces  of  the  drag  and  cope.  Patterns  like 
these  are  arranged  singly  or  in  series  on  plates,  accord- 
ing to  size  and  quantity  required.  A  pattern  of  large  size 
will  occupy  a  plate  to  itself;  several  small  patterns,  alike 
or  dissimilar  in  character,  may  be  arranged  on  one  plate, 
and  poured  from  a  central  ingate  and  spray  of  runners. 

The  difference  between  the  solid  pattern  used  on  a  joint 
board  and  the  divided  pattern  on  a  plate  is  due  to  the 
difference  in  the  methods  of  moulding.  In  the  first  case, 
one-half  the  mould  is  rammed  on  the  other  half — the 
latter  being  the  one  which  is  rammed  on  the  board.  In 
the  second  case  the  mould  parts  are  rammed  independ- 
ently of  each  other,  and  they  do  not  come  together  at  all 
until  finished.  In  both  cases  there  is  much  economy 
over  the  ramming  of  patterns  by  the  ordinary  method  of 


THE  ELEMENTS  OF  MACHINE  MOULDING    265 


turning  over,  in  which  the  joint  has  to  be  prepared  by 
the  trowel  of  the  moulder.  Both  in  joint  board  and  in 
plate  moulding  the  joint  is  made  at  once  by  the  face  of  the 
board  or  plate.  But  the  latter  also  saves  time  in  the  lift- 
ing out  of  numerous  patterns,  besides  which  it  is  a  more 
permanent  arrangement,  and  one  moreover  that  lends 
itself  to  still  further  economies,  as  arrangements  of  run- 
ners and  the  use  of  separate  plates  for  top  and  bottom 


A. 


••€ 


1.---A 


SECTION    A-A 

FIG.  181. — PLATE  MOULDING — TROLLY  WHEEL. 

boxes.  Also  the  system  is  more  adaptable  to  the  pre- 
paration of  patterns  and  plates  in  which  the  joint  faces 
instead  of  being  flat  are  sloped,  curving,  or  otherwise  ir- 
regular in  contour. 

Patterns  are  dowelled  on  plates  (Fig.  182)  just  as  they  are 
when  moulded  by  bedding  in  or  by  turning  over.  Usually 
the  dowels  are  made  long  enough  to  pass  right  through  the 
plates  into  the  holes  of  the  other  half  pattern.  The  pat- 
tern halves  are  fitted  up  with  their  dowels  and  are  tooled 
and  finished  before  being  attached  to  the  plate  A,  which  is 


266 


PRACTICAL  IRON  FOUNDING 


usually  done  with  screws,  or  rivets,  Fig.  182,  sometimes 
with  solder.  In  a  plate  A  fitted  thus  with  pattern  parts 
on  opposite  sides  the  boxes  are  cottered  to  the  plate,  and 


FIG.  182. — PATTERN  PLATE  ON  Box. 

so  rammed,  Fig.  182.  The  cotters  are  then  knocked  out 
and  the  boxes  removed  and  closed  for  pouring.  But 
separate  plates  are  often  used  so  that  two  sets  of  men  can 
be  working  on  one  class  of  castings.  The  positions  of  the 
pattern  parts  are  then  set  on  the  separate  plates  by 


THE  ELEMENTS  OF  MACHINE  MOULDING    267 

centre  lines,  and  the  box  pins  located  properly  so  that 
when  the  half  moulds  are  prepared  they  will  come  to- 
gether without  any  overlapping  joints.  When  patterns  are 


DOOOOU 


FIG.  183. — ARRANGEMENT  OF  SMALL  PATTERNS 
AND  RUNNERS. 

moulded  with  irregular  joint  faces  the  original  pattern  is 
rammed  within  a  suitable  box  and  turned  over  and  the 


FIG.  184— ARRANGEMENT  OF  PATTERNS  AND  RUNNERS. 

other  side  rammed.  Then  a  frame,  prepared  to  the  thick- 
ness of  the  intended  plate,  is  laid  on  the  joint  face  in  the 
box  and  rammed  round  its  edges  to  give  the  size  and 
shape  of  the  plate,  and  the  mould  poured,  so  producing 


268 


PRACTICAL  IRON  FOUNDING 


a  plate  in  one  with  its  pattern.  There  is  no  essential 
difference  in  plate-moulding  and  in  moulding  done  on  a 
machine,  in  fact  the  plates  will  frequently  interchange, 
and  in  the  case  of  small  patterns  several  are  mounted  on 
a  plate  as  in  Figs.  182  to  186,  and  the  runners  also  are 
suitably  disposed  thereon.  Figs.  182  to  184  are  shown  as 
though  mounted  for  plate-moulding  in  ordinary  boxes, 
having  hand  holes,  and  holes  for  the  box  pins.  Fig.  185, 
having  no  holes,  might  be  attached  to  a  moulding  machine 
in  various  ways,  with  clips  or  otherwise.  Also  Fig.  184 


FIG.  185. — ARRANGEMENT  OF  PATTERNS  AND  RUNNERS. 

might  represent  a  single  plate  with  patterns  on  one  side 
only,  two  plates  being  used  on  different  boxes,  or  the  two 
sides  of  the  same  plate  might  be  alike.  Fig.  186  shows 
anvil  jaws  plated  for  use  on  a  machine. 

Fig.  187,  Plate  V,  represents  a  pattern-plate  of  a  loco- 
motive wheel  in  the  background,  while  the  halves  of  the 
mould  made  from  it  are  seen  on  the  ground  in  front. 
Figs.  188  and  189,  Plate  V,  also  show  pattern-plates; 
the  first  is  that  of  a  sprocket  wheel,  the  halves  of  which 
are  on  one  side  of  a  plate.  With  two  rammings  two 
wheels  are  moulded.  The  lower  figure  is  that  of  a  boiler 
door,  made  on  two  separate  plates. 


THE  ELEMENTS  OF  MACHINE  MOULDING    269 


The  utility  of  a  moulding  machine  consists  largely  in 
this,  that  in  place  of  the  clumsy  and  often  inaccurate 
separation  of  the  pattern  plates  from  the  flasks  by  hand, 
there  is  substituted  the  steady,  equal,  and  perfect  separa- 
tion by  mechanism.  Some  of  the  more  useful  machines 
include  much  more  than  this,  as  the  ramming  or  pressing 
of  the  sand  around  the  patterns,  and  the  use  of  stripping 
plates,  that  is,  plates  through  which  the  patterns  are 
drawn,  the  plates  sustain- 
ing the  sand  and  prevent- 
ing broken  edges;  but  such 
elaboration  is  not  essen- 
tial to  machine  moulding, 
though  often  convenient 
and  advantageous. 

The  rapid  growth  of  ma- 
chine moulding  is  one  of 
the  most  remarkable  fea- 
tures of  present  foundry 
practice.  The  machines 
made  now  number  several 
scores  of  distinct  designs, 
though  the  broad  types 

may  be  reduced  to  less  than  a  dozen.  To  understand 
the  essential  differences  between  these  types  it  is  as  well 
to  consider  the  principal  stages  in  making  moulds,  which 
include  ramming,  turning  over,  rapping,  and  withdrawal 
and  closing,  the  dimensions  of  moulds,  and  the  case  of 
repetitive  work.  Each  of  these  aspects  of  moulding  has 
occasioned  the  evolution  of  broad  and  distinct  types  of 
machines,  while  many  machines  are  built  to  combine 
more  than  one  of  these  cardinal  features. 

Ramming. — This  is  the  subject  which  naturally  arises 


o 


FIG.  186. — ANVIL  JAWS 
ARRANGED  ON  PLATE. 


270  PRACTICAL  IEON  FOUNDING 

first  in  any  question  of  machine  moulding.  Because  it  is 
the  most  difficult  feature  to  embody  in  a  machine,  is  the 
reason  why,  notwithstanding  hundreds  of  patented  de- 
vices, only  a  minority  of  machines  to-day  include  pro- 
vision for  complete  mechanical  ramming,  though  the 
number  is  increasing.  The  majority  are  still  built  for 
hand  ramming,  though  these  usually  include  a  presser 
head,  so  that  the  utilities  of  the  moulding  machines  lie 
mainly  in  other  features.  The  exceptions  to  this  general 
rule  lie  chiefly  in  some  special  classes  of  work  which  are 
largely  repetitive,  in  consequence  of  which  considerable 
expense  can  be  incurred  for  blocks  having  irregular  con- 
tours, more  or  less  approximating  to  the  form  of  the 
pattern,  and  by  means  of  which  the  force  of  ramming  can 
be  graduated.  Something  of  this  kind  is  essential,  the 
cases  of  shallow  patterns  excepted,  or  those  with  fairly 
level  faces  over  which  the  sand  can  be  pressed  and  con- 
solidated equally  by  a  flat  pressing  plate.  It  seems 
hardly  necessary  to  explain  the  reason  of  this.  The 
moulder  knows  well  how  the  force  of  ramming  is  varied 
continually,  and  almost  unconsciously  over  different 
sections  of  the  same  mould,  as  well  as  in  moulds  made  of 
different  mixtures  of  sand,  and  that  such  ramming  is 
done  sideways  in  undercut  portions  under  flanges,  lugs, 
bosses  and  so  on,  work  which  no  machine  can  imitate 
perfectly.  Still  it  may  be  stated  that  almost  any  class  of 
work,  even  though  irregular  or  intricate,  can  be  rammed 
by  power  if  the  number  of  castings  required  off  is  suffi- 
ciently numerous  to  warrant  the  cost  of  ramming  appli- 
ances. The  question  then  is  one  of  relative  cost,  as  in 
smiths'  stamping  dies,  and  in  machine  shop  jigs. 

The  reasons  for  adopting  machine  ramming  are  most 
cogent  when  the  joints  of  moulds  are  of  irregular  out- 


THE  ELEMENTS  OF  MACHINE  MOULDING    271 

lines,  that  is,  when  the  faces  of  the  joints  have  to  slope 
upwards  and  downwards,  with  plane  or  curved  outlines 
to  follow  pattern  parts  which  stand  above  or  below  the 
general  plane  of  the  moulding-box  joints.  These  irregu- 
lar joints,  when  made  with  the  trowel  and  the  moulder's 
hands,  often  occupy  a  considerable  time,  and  they  have 
to  be  repeated  for  every  mould  unless  a  ramming  board 
or  block  is  prepared  and  used  for  moulding  on.  When  a 
pattern  plate,  made  in  a  similar  way,  is  put  on  a  mould- 
ing machine,  the  economy  of  power  ramming  is  very 
great.  And  further,  on  the  same  joint  plate,  runners, 
or  sprays  of  runners,  are  usually  arranged  once  for  all,  so 
effecting  a  further  economy  in  time. 

Turning-over. — The  turning-over  of  the  parts  of  mould- 
ing boxes,  when  done  by  a  machine,  avoids  the  risk  of 
the  sudden  shock  and  fracture  of  sand  which  sometimes 
follows  from  a  clumsy  turn-over  done  by  hand.  Some- 
times it  is  the  pattern  plate  alone  that  is  turned  over, 
sometimes  the  moulding  box  on  the  plate.  But  in  any 
case  it  is  always  done  steadily,  and  the  plate,  or  the  box, 
is  locked  in  a  truly  horizontal  position,  and  also  at  a 
height  convenient  for  working  at,  instead  of  lying  down 
on  the  ground.  This  last  is  one  of  the  less  appreciated 
features  of  machine  moulding,  but  it  nevertheless  has 
considerable  advantages. 

The  turn-over  table  is  fitted  to  the  greater  number  of 
machines  designed  for  general  use,  because  it  affords  the 
handiest  method  of  ramming  tops  and  bottoms.  But  as 
machines  increase  in  dimensions,  its  weight  becomes 
objectionable,  and  the  largest  machines  therefore,  as  well 
as  many  of  medium  sizes,  employ  a  non-turnover  type  of 
table.  Then  tops  and  bottoms  can  be  rammed  on  separate 
machines,  or  on  one  machine  at  different  times,  or  at 


272  PRACTICAL  IRON  FOUNDING 

the  same  time  if  the  length  of  the  table  is  sufficient  to 
receive  two  boxes  side  by  side,  which  is  often  arranged. 

A  large  machine,  with  a  non-turnover  table,  is  often 
preferred  to  two  or  more  smaller  ones,  because  several 
patterns  can  be  moulded  at  one  time  on  one  or  on 
separate  plates.  This  is  an  extension  of  the  method 
adopted  in  hand  work,  of  arranging  several  small 
patterns  in  one  moulding  box,  or  on  one  bottom  board  or 
plate. 

Rapping  and  Withdraw- al. —  The  delivery  of  patterns 
from  moulds  when  done  by  hand  is  commonly  a  cause 
of  enlargement,  and  variations  in  the  sizes  of  moulds, 
and  often  of  fracture  of  the  sand,  which  when  mended 
up  tends  to  produce  variations  in  the  dimensions  of 
moulds.  The  larger  a  mould  is,  the  more  risk  is  there 
of  such  accidents  happening,  because  of  the  difficulty  of 
getting  a  truly  level  lift  when  two  or  three  men  are  lift- 
ing at  once,  or  when  the  crane  has  to  withdraw  a  pattern. 
The  principal  value  of  very  many  moulding  machines, 
therefore,  lies  in  the  simple  fact  that  patterns  and 
moulds  are  separated  by  the  coercion  of  rigid  slides  in- 
stead of  by  the  unsteady  action  of  the  human  hand,  or  of 
the  crane.  So  valuable  is  this  feature  that  many  mould- 
ing machines  embody  no  other  provision  besides  this. 
Subject  to  the  condition  that  patterns  are  made  well, 
there  is  no  fracture  of  sand,  and  a  hundred  moulds 
made  from  the  same  pattern  will  show  no  variations  in 
size. 

But  there  are  aids  to  the  withdrawal  of  some  kinds  of 
patterns  which  are  essential.  A  deep  pattern  having 
little  or  no  taper  or  draught  cannot  be  withdrawn  with  - 
out  tearing  up  the  edges  of  the  sand  unless  some  rap- 
ping or  vibration  is  imparted  to  it,  or  unless  a  stripping 


"V 


THE  ELEMENTS  OF  MACHINE  MOULDING    273 

plate  is  used  to  hold  down  the  sand  around  its  edges. 
Shallow  patterns  and  those  which  are  well  tapered  can 
be  withdrawn  readily  if  the  machine  plate  on  which  the 
pattern  is  mounted  is  rapped  with  a  wooden  mallet 
during  the  act  of  withdrawal,  and  this  is  usually  done. 
But  that  is  a  different  thing  from  the  lateral  rapping 
with  an  iron  bar  inserted  in  the  pattern,  and  which  is 
imparted  previous  to  the  lifting  by  hand  of  the  pattern 
from  an  ordinary  mould.  Eapping  on  the  plate  merely 
loosens  the  sand  next  the  pattern  and  prevents  its  ad- 
herence. But  slight  enlargement  of  the  mould,  imitat- 
ing the  action  of  the  rapping  bar  is  provided  for  in  the 
jarring  or  vibrating  class  of  machines  in  which  slight 
lateral  rapid  movements  are  imparted. 

The  majority  of  machines  have  no  provision  for  vibrat- 
ing the  pattern,  but  when  deep  lifts  have  to  be  made  of 
patterns  provided  with  little  or  no  taper,  a  stripping 
plate  is  made  to  encircle  the  pattern  closely.  It  is  laid 
on  the  face  of  the  mould  and  the  pattern  is  withdrawn 
through  the  plate.  This  is  an  extension  of  the  method 
often  adopted  in  making  common  moulds  by  hand  work, 
when  strips  of  wood  are  laid  down  along  the  edges  of 
the  mould  beside  the  pattern,  and  retained  by  weights 
during  the  withdrawal  of  the  pattern.  The  sand  around 
the  edges  is  thus  prevented  from  being  torn  up  by  the 
lifting  of  the  pattern.  Frequently  metal  stripping  plates 
are  used  for  hand  moulds,  as  in  machine  moulding, — in 
some  gear  wheels  for  example,  both  of  spur,  and  special 
types.  These  are  rather  expensive,  being  filed  out  of 
sheet  metal  to  embrace  and  fit  the  pattern  outlines, 
hence  they  bear  a  high  proportion  to  the  cost  of  the 
castings  unless  a  large  number  are  required.  But  many 
are  made  now  cheaply  by  casting  white  metal  within  an 


274  PRACTICAL  IEON  FOUNDING 

iron  frame  surrounding  the  pattern.  And  so  when  the 
inaccuracies  which  result  from  hand  rapping  and  with- 
drawal are  eliminated  by  machine  moulding,  castings 
are  more  uniform  in  size  and  shape.  Hence  the  allow- 
ances for  tooling  can  be  lessened,  with  reduction  of  costs 
in  the  machine  shop. 

The  idea  of  drawing  the  pattern  through  a  plate  has 
been  familiar  for  the  past  forty  years  or  more,  even  in 
hand  work.  The  late  Mr.  James  Howard,  of  the  firm  of 
James  and  Frederick  Howard,  of  Bedford,  took  out  a 
British  patent  for  a  moulding  machine  worked  on  this 
principle  as  far  back  as  1856,  and  that  firm  has  used 
machines  of  this  type  ever  since  for  the  bulk  of  their 
repetition  work. 

Closing. — Moulds  are  usually  closed  by  hand.  But  a 
few  machines  are  made  to  fulfil  this  function  after  the 
removal  of  the  box  parts  from  the  moulding  machine. 
There  are, -however,  apart  from  this,  many  adjuncts  to 
machines  for  taking  the  finished  moulds  away  for 
closing  them,  as  trolly  tracks,  turn-tables,  etc. 

Dimensions. — The  dimensions  of  moulds  impose  some 
limitations  on  the  sizes  of  moulding  machines,  though 
a  large  increase  in  size  has  been  noticeable  in  recent 
years,  chiefly  in  some  American  and  German  machines. 
All  the  early  machines  were  designed  only  for  dealing  with 
articles  of  small  dimensions,  not  exceeding  from  about 
2  ft.  to  3  ft.  across,  and  the  greater  number  moulded  were 
even  smaller  than  that.  The  reason  is  obvious,  since 
the  first  machines  were  operated  by  hand  alone.  After 
power  was  applied,  dimensions  increased,  and  the  largest 
machines  now,  which  will  take  lengths  of  10  ft.  to  15  ft., 
are  operated  by  hydraulic  pressure  with  the  greatest  ease. 
A  large  machine  has  the  advantage  over  a  small  one 


THE  ELEMENTS  OF  MACHINE  MOULDING    275 

that  it  is  adaptable  for  dealing  with  single  moulds  of 
the  largest  size  within  its  capacity,  as  well  as  with  two 
or  more  separate  moulds  of  smaller  dimensions,  thus 
combining  in  one  the  advantages  of  two  machines. 

Repetition. — The  production  of  repetitive  work  on  a 
large  scale  has  been  the  cause  of  the  development  of  the 
portable  types  of  machines,  of  multiple  moulding,  and 
of  numerous  adjuncts  to  fixed  machines  of  ordinary  and 
of  special  types,  such  as  tracks,  conveying  systems, 
cranes,  etc.  This  aspect  alone  opens  up  a  very  wide 
field  of  interesting  detail  which  illustrates  the  numerous 
and  varied  ways  in  which  similar  results  are  secured. 
For  though  the  small  light  machines  may  be  moved 
along  the  floor,  leaving  their  work  behind  them,  the 
large  heavy  ones  must  be  fixtures,  and  the  work  must 
be  brought  to  and  conveyed  from  them.  Convey  ing- 
systems  also  deal  with  the  sand  and  the  moulding  boxes. 
In  some  shops  these  systems  have  become  very  highly 
developed. 

Adaptability. — The  practice  of  machine  moulding  is 
adaptable  to  all  classes  of  work  that  lie  within  the 
capacities  of  the  machines.  Like  die-forging,  it  is  suit- 
able alike  for  a  limited  number  of  articles  only,  or  for 
hundreds  or  thousands  of  similar  parts.  And  the  cost  of 
the  pattern  work  is  mainly  controlled  by  the  numbers 
of  castings  required;  ordinary  cheap  patterns  of  wood 
for  a  few  moulds;  high-class,  well  made  patterns  of  metal 
when  hundreds  or  thousands  of  moulds  have  to  be  taken 
therefrom.  So  that  moulding  machine  practice  ranges 
from  that  in  which  ordinary  patterns  are  mounted  on 
plates,  as  in  the  plate-moulding  which  is  done  by  hand, 
and  put  on  the  machine,  to  those  in  which  metal  patterns 
on  plates  are  got  up  in  the  best  possible  manner  for  use 


276  PRACTICAL  IRON  FOUNDING 

on  the  machine  alone.  And  between  these  extremes 
every  grade  and  method  of  pattern  work  is  represented 
in  machine  moulding.  Formerly,  too,  only  simple  pat- 
terns were  attempted,  but  now  many  intricate  forms  are 
used.  The  simplification  of  the  moulder's  task  also 
follows,  with  the  result  that  men  who  have  not  had 
the  moulder's  training,  or  mastered  any  section  of  the 
moulder's  craft,  are  able  in  a  few  weeks  to  operate 
machines. 

Patterns. — As  in  ordinary  hand  moulding,  patterns 
are  either  unjointed  or  jointed.  In  the  first  case  a  plain 
top  only  is  wanted,  and  then  the  pattern  is  mounted  on 
one  side  of  a  plate.  In  the  second  case  the  pattern  parts 
or  halves,  as  the  case  may  be,  are  mounted  on  opposite 
sides  of  one  plate,  or  each  on  one  side  of  two  distinct 
plates,  which  may  be  moulded  on  the  same  machine  by 
one  man,  or  on  different  machines  by  different  men. 
The  matching  of  the  moulds  depends  on  the  degree  of 
care  and  accuracy  with  which  the  pattern  maker  has 
done  his  work.  Each  of  these  methods  is  also  adopted  in 
much  hand  moulding  when  it  is  of  a  repetitive  character. 
Another  fact  is  that  in  moulding  by  machine  it  does  not 
matter  essentially  whether  the  pattern  is  lifted  from  the 
mould,  or  whether  the  mould  is  withdrawn  from  the 
pattern,  and  whether  upwards  or  downwards.  Neither, 
as  already  stated,  is  turning  over  on  the  machine  an  essen- 
tial. The  details  vary  with  types  of  machines. 

A  point  to  be  emphasized  is  the  futility  of  pinning 
one's  faith  and  practice  to  one  class  of  machine.  No 
matter  how  excellently  designed  and  economical  a  machine 
is,  there  is  always  another  that  will  go  a  point  better  on 
certain  classes  of  work,  and  operated  under  different 
conditions.  That  is  the  reason  why  a  firm  should  feel 


THE  ELEMENTS  OF  MACHINE  MOULDING     277 

its  way  in  laying  down  plant  of  this  character,  and  not 
order  a  lot  of  machines  of  one  type,  if  the  range  of  work 
done  is  of  a  varied  kind.  The  case  is  paralleled  by  that 
of  machine  tools.  No  sane  manager  would  fill  a  shop 
with  machines  of  one  build  and  type,  unless,  of  course, 
the  character  of  the  work  done  was  uniform,  as  in  the 
case,  say,  of  ranges  of  screw  machines,  or  gear  cutters, 
always  operating  on  the  same  kinds  and  nearly  the  same 
sizes  of  work. 

The  question  of  type  of  machine  then  opened  up  is  a 
very  wide  one.  So  is  that  of  dimensions.  So,  too,  is 
that  of  method  of  operation.  Thus,  if  men  work  regu- 
larly on  separate  parts  of  the  same  moulds,  on  separate 
machines,  there  is  no  need,  as  a  rule,  to  have  turn-over 
table  machines.  Nor  when  tops  are  uniformly  plain 
are  turn-over  machines  necessary.  Nor  when  the  two 
parts  of  moulds  are  made  side  by  side  on  one  plate,  or 
when  a  number  of  tops  and  then  a  number  of  bottoms 
are  made  on  the  same  machine,  is  it  necessary  to  have 
a  turn-over  table. 

With  regard,  again,  to  dimensions,  the  size  of  a  single 
pattern  alone  is  not  only  the  governing  question,  since 
it  is  often  more  economical  to  put  several  patterns  on 
one  large  machine  than  to  have  single  patterns  on  smaller 
machines.  This  holds  good  not  only  in  relation  to  very 
small  patterns  that  are  commonly  grouped  thus,  but 
to  those  of  comparatively  large  dimensions,  which  can 
be  moulded  on  oblong  machines  of  several  feet  in  length. 
Another  advantage  in  using  such  machines  is  that  top 
and  bottom  box  parts  may  be,  and  often  are,  rammed 
on  one  side  of  one  plate  at  once,  not  of  the  turn-over 
type. 

The  method  of  operation  is  an  important  governing 


278  PRACTICAL  IRON  FOUNDING 

condition  when  we  get  into  machines  of  very  large 
dimensions,  for  it  is  obvious  that  however  well  counter- 
balanced a  table  may  be,  and  though  human  power  may 
be  multiplied  and  used  to  the  best  advantage,  with 
levers  and  with  worm  gear,  there  is  a  limit  to  its  em- 
ployment beyond  which  hand  operations  cannot  be 
conveniently  and  economically  carried,  and  this  is  the 
opportunity  for  the  power  machine,  and  this  raises  the 
broad  question  of  power  operation. 

Generally  this  should  be  settled  by  the  character  of 
the  plant  already  existing  in  a  shop,  or  of  that  which 
it  may  be  contemplating  to  lay  down.  All  progressive 
foundries  are  now  equipped  with  power  of  some  kind,  as 
steam  or  water  power  for  cranes,  air  or  electricity  for 
hoists,  and  other  purposes.  Of  hydraulic  moulding 
machines  there  is  an  immensely  greater  choice  than  there 
is  as  yet  of  steam  or  of  pneumatic  machines.  But  in 
view  of  the  recent  rapid  growth  of  air-operated  machinery 
which  has  been  shared  by  the  foundry  in  common  with 
other  departments,  we  may  anticipate  that  pneumatic 
moulding  machines  will  be  in  much  greater  demand  in 
the  future  than  they  are  yet.  If  the  question  is  one  of 
laying  down  power  plant  in  a  foundry  as  yet  unsupplied 
with  power,  it  may  be  pointed  out  that  a  pneumatic 
plant  is  less  expensive  and  less  bulky  than  a  hydraulic 
one.  Air-compressing  plants  are  very  suitable  for  small 
foundries,  and  they  serve  also  for  hose-piping  for  blowing 
out  moulds,  in  place  of  bellows:  and  a  few  air  hoists 
also  are  more  handy  than  fixed  hydraulic  cranes.  None 
of  these  questions  can  be  settled  offhand,  but  each  separ- 
ate shop  must  work  out  its  own  problems,  independently 
of  the  governing  conditions  of  others. 


CHAPTER  XIV 

EXAMPLES  OF  MOULDING  MACHINES 

FIG.  190,  Plate  VI,  illustrates  one  of  the  simplest 
machines  that  can  be  made,  being  a  mould  press  simply. 
Ordinary  boxes  and  snap  flasks  are  moulded  on  it,  the 
latter  being  shown  in  place.  Preliminary  ramming  may 
or  may  not  be  done  by  hand,  according  to  the  outline  of 
the  pattern.  The  final  pressure  is  imparted  to  the  top 
and  bottom  of  the  moulds,  to  which  presser-boards  are 
fitted,  by  the  downward  pressure  of  the  hinged  head, 
actuated  through  toggle  levers  by  hand.  The  levers  on 
opposite  sides  of  the  machine  are  connected  by  a  hori- 
zontal shaft.  The  height  of  the  presser-head  is  adjusted 
to  suit  boxes  of  different  depths  by  means  of  the  nuts  on 
the  screwed  rods.  There  is  no  mechanical  delivery, 
patterns  being  rapped  and  withdrawn  by  hand  in  the 
ordinary  way.  But  the  saving  in  time  is  very  consider- 
able on  repetitive  work. 

A  hand  machine  of  more  advanced  type,  which  has 
been  in  successful  use  during  many  years,  is  that  manu- 
factured by  Messrs.  Darling  and  Sellers,  Limited,  of 
Keighley.  It  is  made  in  a  large  range  of  dimensions,  both 
for  general  work,  for  specially  deep  work,  and  for  strip- 
ping plates.  The  machine  is  designed  for  hand  ramming, 
and  no  special  pattern  plates  are  necessary,  since  any 
patterns  of  suitable  size,  either  in  wood  or  metal,  can  be 
mounted  on  the  table.  The  illustration,  Fig.  191,  Plate 

279 


280  PRACTICAL  IRON  FOUNDING 

VI,  shows  one  of  these  machines,  which  is  specially  de- 
signed to  take  deep  and  heavy  boxes,  with  which  object 
it  is  made  rather  differently  from  those  which  are  built  for 
small  and  medium  work  of  a  general  character,  as  in  Fig. 
192,  Plate  VII.  It  will  be  noted  that  though  the  general 
design  is  similar  in  both  instances,  the  differences  are 
that  gearing  is  used  in  Fig.  191  for  operating  the  turn- 
over table,  and  that  the  elevation  is  done  by  racks  and 
gears  instead  of  by  simple  movements  of  a  lever,  as  in 
Fig.  192.  But  with  these  exceptions  the  same  general 
description  will  apply  to  each. 

The  two  standards  in  these  illustrations  carry  the 
mechanism  between  them;  they  are  built  at  various 
distances  apart,  ranging  from  30  in.  upwards  to  about 
16  ft.,  to  suit  boxes  of  different  lengths,  and  are  main- 
tained apart  by  stretcher  bolts  and  a  bottom  casting, 
while  the  larger  machines  are  also  bolted  to  a  base- 
plate. The  pattern  is  fixed  to  the  upper  face  of  the  top 
table,  which  is  of  the  turn-over  type,  and  the  box  is 
placed  over  this  and  rammed  by  hand.  It  is  retained  in 
place  by  means  of  screws  and  sockets  which  are  adjust- 
able for  different  depths  of  boxes,  or  in  the  case  of  light 
work,  by  spring  clips.  The  table  is  fitted  with  trunnions 
of  large  diameter,  in  capped  bearings  in  the  standards. 
Set  screws,  with  large  nuts,  afford  the  means  by  which 
the  table  is  adjusted  for  level  without  further  check,  and 
it  is  prevented  from  moving  by  the  catch  handles  above. 
In  the  machines  for  general  service  the  trunnions  are 
placed  in  the  centre  of  the  table,  as  in  Fig.  192.  But 
in  the  example  in  Fig.  191  they  are  placed  eccentrically 
in  order  to  come  more  in  line  with  the  weight  of  the 
pattern  and  moulding  box.  But  they  are  arranged  in  or 
out  of  centre,  in  either  machine,  to  suit  requirements. 


EXAMPLES  OF  MOULDING  MACHINES      281 

When  the  pattern  has  been  rammed,  the  catches  above 
are  removed,  the  table  is  turned  through  half  a  revolu- 
tion and  relocked,  leaving  the  moulding  box  with  its 
contained  mould  and  pattern  suspended  from  the  under- 
side of  the  table.  At  this  stage  another  portion  of  the 
mechanism,  the  lifting  table,  the  bottom  one,  in  both 
figures,  is  brought  into  operation.  This  is  a  ribbed  plate, 
underneath  which  two  turned  stems  or  pillars,  seen  in 
Fig.  191,  are  attached  with  bolts  through  flanged  ends 
on  the  pillars.  These  are  the  means  by  which  the 
lifting  table  is  elevated  and  depressed  through  the 
action  of  slotted  links  hidden  within  the  base,  actuated 
by  two  levers  on  a  horizontal  shaft,  which  is  turned 
by  the  long  lever  seen  to  the  left  in  Fig.  192.  The  total 
mass  of  these  parts  is  counterbalanced  by  the  weight 
seen  at  the  right.  The  effect  of  moving  the  lever  is  to 
bring  the  table  up  towards  the  back  of  the  box  that  has 
just  been  rammed.  In  the  deeper  class  of  machines 
shewn  in  Fig.  191,  the  table  is  lifted  by  cylindrical  racks 
seen  beneath.  These  slide  in  bored  sockets,  and  are 
actuated  by  the  hand  wheel  and  gears  to  the  left  of  that 
illustration.  The  raising  and  lowering  of  the  table  are 
performed  with  ease,  because  the  weight  of  the  latter, 
together  with  that  of  its  load,  is  counterbalanced  by 
adjustable  weights,  which  descend  into  the  founda- 
tions. 

The  table  is  lifted  up  until  it  presses  the  carriage 
against  the  back  of  the  rammed  box.  The  clamps  are 
then  released  and  the  table  lowered,  the  mould  descend- 
ing with  it  away  from  the  pattern.  During  the  period  of 
this  delivery  the  upper  surface  of  the  turn-over  table  is 
rapped  with  a  mallet  to  assist  the  separation  of  the 
pattern  from  the  sand. 


282  PRACTICAL  IRON  FOUNDING 

The  mould  is  now  left  lying  on  the  carriage,  imme- 
diately above  the  lower  table,  on  which  it  is  drawn  away 
by  means  of  rollers  beneath  the  latter,  not  visible,  to  the 
receiving  rails  in  front,  which,  being  clear  of  the  machine, 
permits  the  mould  to  be  lifted  off  and  taken  away. 
The  carriage  is  of  wood,  and  its  movement  is  controlled 
by  flanges  on  the  ends  of  the  table.  The  receiving  rails 
are  similarly  flanged,  and  form  the  top  edges  of  cast- 
iron  brackets,  which  are  bolted  to  the  front  of  the 
machine.  The  empty  carriage  is  now  pushed  back  on 
the  lifting  table,  and  the  turn -over  table  revolved  to 
bring  the  pattern  on  its  upper  face  ready  for  the 
next  box. 

Front  and  back  plates  enclose  the  lower  portion  of  the 
machine.  These  are  fitted  by  planed  joints  to  the 
standards,  and  serve  the  double  purpose  of  bracing  the 
machine  and  preventing  sand  from  falling  inside. 
Inner  sloping  top  edges  of  these  plates  shoot  off  any  sand 
that  falls  from  above.  A  handy  table  is  supported  on 
brackets  at  one  side,  Fig.  192,  to  carry  the  moulders' 
tools,  swab  pot,  blacking  bag,  etc. 

A  machine  of  this  kind  is  of  great  value  in  any  foundry, 
even  where  few  specialities  are  handled.  Any  ordinary 
pattern  within  its  range  can  be  taken  and  put  on  the 
table  and  moulded  with  a  perfectly  vertical  lift.  It  will 
pay  to  use  the  machine  for  two  or  three  moulds  only. 
When  a  plain  top  only  is  required,  the  latter  can  be 
rammed  on  the  plain  table.  When  patterns  are  jointed, 
their  halves  or  parts  must  be  fitted  on  apposite  sides  of 
the  table,  or  be  fixed  on  separate  machines,  which  in- 
volves some  fitting  that  would  not  be  justified  for  two 
or  three  castings,  though  in  this  respect  the  machine  is 
quite  adaptable  in  firms  that  have  not  much  specializa- 


EXAMPLES  OF  MOULDING  MACHINES      283 

tion.  But  outside  of  these  there  are  many  cases  in  which 
the  patterns  are  cast  with  the  turn-over  or  swivel  table, 
as  in  labour-saving  repetition  work.  Patterns  are 
specially  mounted  in  three  ways — on  &  false-part  box,  or 
on  thin  cast-iron  plates  exactly  as  used  in  many  shops 
for  plate  moulding  without  the  assistance  of  a  machine, 
or  mounted  in  plaster-of-paris. 

In  all  these  cases  the  piece  carrying  the  pattern  or 
patterns  is  capable  of  being  attached  simply  and  rapidly 
to  the  turn-over  table  by  a  couple  of  bolts,  and  the  usual 
practice  is  to  mount  the  bottom-part  pattern  on  the 
table,  make  the  required  number  of  half-moulds,  and  then 
replace  it  by  the  top-part  pattern;  the  change  of  patterns 
being  only  the  work  of  a  few  minutes. 

Messrs.  Woolnough  and  Dehne's  moulding  machine, 
manufactured  by  Messrs.  Samuelson  and  Co.,  Ltd.,  of 
Banbury,  is  illustrated  in  Fig.  193,  Plate  VII,  and  Figs. 
194  and  195,  p.  285.  Fig.  193  is  a  perspective  view  of 
the  machine,  Fig.  194  a  sectional  elevation  of  one  of  the 
standards,  Fig.  195  a  horizontal  section  through  the 
standard  on  the  line  A-B.  A  base  plate,  Fig.  193  carries 
a  couple  of  pillars,  one  of  which,  that  to  the  right,  is 
permanently  fixed,  the  other,  to  the  left,  is  capable  of 
horizontal  movement,  rendering  the  machine  adjustable 
to  the  width  of  any  pattern  plates  within  its  range.  The 
pillars  Ay  are  hollow,  enclosing  spindles  B,  to  which 
vertical  movement  can  be  imparted  by  means  of  the 
weighted  lever  handle  seen  in  Fig.  193.  The  lever  actu- 
ates the  horizontal  shaft  H9  Figs.  194  and  195,  upon 
which  are  keyed  two  worm  wheels  F,  enclosed  in  the 
semicircular  casings  G.  The  shaft  and  casings  are  seen 
at  the  front  in  Fig.  193.  The  worm  wheels  engage  with 
screws  cut  on  the  vertical  spindles  B,  and  so  raise  and 


281  PRACTICAL  IRON  FOUNDING 

lower  the  pattern  plate,  which  has  its  bearings,  c,  in  the 
upper  ends  of  the  spindles,  and  which  can  be  turned  over 
in  its  bearings.  Two  triangular  plates  furnished  with  slots 
and  bolts  for  vertical  adjustment  slide  in  faces  upon  the 
pillars,  Fig.  193,  and  their  upper  edges  form  the  tracks 
for  the  wheels  of  the  plate,  upon  which  the  moulding  box 
is  supported.  The  provision  for  vertical  adjustment  per- 
mits of  the  employment  of  flasks  at  various  depths. 

The  method  of  moulding  is  as  follows:  That  face  of 
the  pattern  plate  from  which  the  impression  is  to  be 
immediately  taken,  whether  for  cope  or  drag,  is  turned 
uppermost,  and  the  appropriate  flask  placed  thereon  and 
clamped  or  screwed.  The  sand  is  then  rammed  in  by 
hand,  and  scraped  level.  The  flask  and  plate  are  turned 
bodily  over  and  lowered,  until  the  back  of  the  flask  rests 
upon  the  table  beneath.  The  pattern  plate  is  then  pinched 
in  its  bearings  with  the  set  screws  seen  at  the  tops  of  the 
pillars,  and  lifted  clear  of  the  flask  by  the  lever  handle. 
A  very  slight  amount  of  rapping  is  imparted  to  the  pat- 
tern plate  in  the  act  of  withdrawal.  When  the  mould  has 
been  blackened  the  pattern  may  be  returned  temporarily 
in  order  to  press  the  blackening  down,  thus  saving  the 
trouble  of  sleeking. 

The  sleeve,  D,  Fig.  194,  is  simply  for  the  purpose  of 
protecting  the  vertical  spindles  from  access  of  dust,  and 
a  screw  gland,  E,  similarly  protects  the  worm  and  worm 
wheel. 

Fig.  196,  Plate  VIII,  shows  a  machine  of  a  similar  type 
by  the  London  Emery  Works  Company,  carrying  the 
pattern  for  tramway  axle  boxes,  castings  of  which  are 
seen  in  the  foreground.  The  tubular  standards  each  en- 
close a  flat  threaded  spindle,  the  top  of  which  is  formed 
into  bearings  to  receive  the  trunnions  of  the  turn- over 


Fia.  195.          FIG.  194 

WOOLNOUGH  AND  DEHNE's  MOULDING  MACHINE. 

SECTIONAL  VIEWS. 


286  PRACTICAL  IRON  FOUNDING 

table  on  which  the  box  parts  are  rammed.  The  racks  are 
moved  in  unison  by  the  long  weighted  hand  lever  seen  at 
the  left,  which  lever  is  adjustable  by  bolt  holes  into  five 
different  angular  positions  to  suit  different  amounts  of 
lift.  The  moving  mass  is  counter  weighted  at  each  end  ; 
the  chains  to  which  the  counterweights  are  attached  lead 
off  from  pulleys  one  on  each  end  of  the  gear  shaft  below, 
leading  to  pulleys  above.  The  box  being  rammed  upper- 
most, by  hand,  is  then  turned  over,  and  lowered  by  the 
lever  on  to  a  trolly  below,  the  box  being  ran  away  after 
the  pattern  has  been  delivered. 

The  general  type  of  the  Pridmore  machines  is  that  in 
which  the  table  does  not  turn  over,  and  in  which  a  strip- 
ping plate  is  used  in  all  except  shallow  work.  A  frame 
standing  on  the  floor  by  legs,  or  a  claw  foot,  carries  the 
stripping  plate,  and  is  fitted  with  a  yoke  or  plunger 
which  carries  the  pattern,  and  by  means  of  a  crank  or 
cranks  operated  by  a  lever,  the  yoke  is  drawn  down  or 
raised  with  the  patterns.  The  depth  of  draw  is  capable 
of  adjustment,  and  the  pattern  can  be  adjusted  for  height 
in  relation  to  the  stripping  plate.  No  vibration  or  rapping 
is  required. 

The  broad  plan  followed  in  the  construction  of  the  small 
and  medium-size  machines  may  be  clearly  understood 
from  the  photograph  Fig.  197,  Plate  IX,  which  shows, 
to  the  right,  one  of  the  smaller  sizes  of  "  square  "  machines 
with  a  pattern  mounting,  to  which  further  reference  will 
be  made;  and  a  rock-over  machine  to  the  left  of  the  figure. 
Figs.  198  to  200  illustrate  one  of  the  12  in.  "round" 
machines,  in  side  and  front  elevation  and  plan  respect- 
ively. The  essential  construction  of  each  is  identical, 
unaffected  by  the  square  or  round  shape  of  the  framings. 

The  design  is  that  of  a  main  frame,  A,  formed  of  a 


EXAMPLES  OF  MOULDING  MACHINES      287 

single  casting,  and  a  pattern-carrying  yoke,  B,  consist- 
ing of  a  second   single   casting,  which  is  lowered   and 


FIG.  198. — PRIDMORE  MACHINE.    SIDE  ELEVATION. 

raised  within  the  main  frame  by  a  crank,  C,  and  pitman, 
D.  The  yoke,  B,  is  guided  at  the  top  in  adjustable  ways, 
a,  a,  and  at  the  bottom  of  the  frame  in  a  round,  brass- 
bushed  guideway,  b.  The  distance  between  the  upper  and 


288 


PRACTICAL  IRON  FOUNDING 


the  lower  guides  being  great  in  proportion  to  the  width  of 
the  frame,  ensures  a  true  draw.  The  crank- shaft,  E,  upon 
which  depends  the  weight  of  the  yoke  and  the  patterns, 


FIG.  199. — PRIDMORE  MACHINE.    END  ELEVATION. 

through  the  crank  and  pitman,  is  journal  led  in  a  long 
brass-bushed  bearing,  F,  extending  one-half  of  the  width 
of  the  machine,  and  cast  solid  with  the  main  frame.  The 
yoke  when  raised  is  locked  securely  in  position  for  ram- 


EXAMPLES  OF  MOULDING  MACHINES      289 

ming  the  mould  by  the  crank  passing  slightly  beyond 
the  centre  and  bearing  on  the  edge.  The  amount  of  draw 
can  be  adjusted  to  the  height  of  the  patterns  by  a  simple 
bolt,  G,  and  set-nut.  Any  wear  upon  the  crankshaft  or 
pin,  or  yoke  pin,  can  be  taken  up  by  an  eccentric  brass 
bushing  on  the  yoke  pin,  with  a  series  of  holes  register- 
ing with  differential  holes  in  the  pitman,  M,  so  that  all 
wear  can  be  adjusted  to  one-five-hundredth  of  an  inch. 


FIG.  200. — PRIDMORE  MACHINE.    PLAN. 

Wear  on  the  guideways,  a,  is  taken  up  by  adjustable 
plates,  K,  which  are  set  along  horizontally  and  pinched 
with  the  bolts,  d.  The  machine  is  supported  on  a  claw 
foot,  L. 

The  various  types  in  which  these  are  made  are  as 
follows,  classified  broadly  as  "light"  and  "heavy" 
machines: 

The  light  machines,  supported  centrally  on  a  claw- 
like  foot,  are  of  either  round  or  square  outline.  The 

u 


290  PRACTICAL  IRON  FOUNDING 

round  ones  are  made  to  take  circular  patterns,  such  as 
gear  wheels,  pulleys,  and  similar  classes  of  work — in 
diameters  ranging  from  10  to  20  in.,  and  with  a  depth  of 
face  not  exceeding  10  in.  The  depth  of  draw  is  4f  in. 
The  yoke  is  controlled  by  two  guideways  above  and  one 
in  the  centre,  with  a  single  crank.  The  square  ones  also 
take  10  in.  in  depth  with  a  draw  of  4f  in.,  and  range  in 
capacity  from  9  in. +  12  in.  to  18  in. +  28  in.,  the  general 
construction  being  similar. 

Oblong  machines  are  made  of  square  type,  but  are  sup- 
ported on  two  legs  or  standards,  one  at  each  end,  with 
the  yoke  duplicated  over  and  within  each  standard,  con- 
nected with  a  central  shaft,  and  operated  by  a  single 
crank  at  one  end.  They  have  the  same  draw — 4£  in.— 
and  they  embrace  patterns  from  12  in.  to  20  in.  in  width 
and  from  24  in.  to  48  in.  in  length,  and  larger  to  order. 

The  frames  of  all  square  or  rectangular  machines  are 
left  open  at  the  ends,  thereby  permitting  the  use  of 
patterns  which  are  considerably  longer  than  the  frame 
of  the  machine.  The  stripping  plate  setting  upon  the  top 
of  the  frame  is  not  limited  to  any  particular  size,  so  that 
a  wide  range  in  sizes  of  boxes  is  permitted. 

The  foregoing  form  a  class  of  machines  which  are  com- 
paratively light,  have  but  one  crankshaft,  and  with  the 
exception  just  named  have  shallow  draws  and  high 
tables,  and  are  adapted  to  work  of  small  and  medium 
dimensions. 

There  is  another  large  class  having  characteristics  of 
an  opposite  character,  being  "heavy,"  and  suitably  de- 
signed for  heavy  work  (Fig.  201,  Plate  IX).  These  illus- 
trate a  machine  in  which  a  wooden  pattern  is  mounted 
with  a  wooden  stripping  plate,  a  method  suitable  for  oc- 
casional work. 


EXAMPLES  OF  MOULDING  MACHINES      291 

These  machines  consist  of  single  heavy  castings  for 
the  main  frame,  standing  upon  legs  at  each  corner.  The 
frame  is  rigidly  designed,  which  is  essential  in  all  mould- 
ing machines.  Want  of  rigidity,  causing  the  pattern  to 
swing,  and  the  moulding  box  to  register  imperfectly,  has 
been  the  cause  of  the  inefficiency  of  some  moulding  ma- 
chines. The  "  heavy"  machines  are  square,  oblong,  or 
round,  but  the  yoke  which  raises  and  lowers  the  pattern 
or  patterns  is  operated  by  two  parallel  crankshafts  and 
four  guideways,  or  six  in  some  of  the  longer  machines. 
In  these,  too,  the  yoke  upon  which  the  patterns  are 
mounted  is  a  second  single  large  casting.  The  yokes  slide 
in  guideways  on  the  inside  faces  near  the  ends  of  the 
parallel  sides  of  the  main  frames,  on  the  top  edges  of 
which  the  stripping  plate  frame  is  mounted.  Long  bear- 
ings are  cast  in  each  corner  of  the  main  frame,  close  to 
the  legs,  and  in  these  bearings  are  fitted  two  heavy  par- 
allel shafts.  Upon  each  end  of  each  of  these  shafts,  set- 
ting close  to  the  bearings,  is  keyed  a  double-ended  crank; 
in  the  upper  ends  of  these  cranks  are  pins  upon  which 
are  journalled  heavy  pitmans,  the  upper  ends  of  the  pit- 
mans  being  journalled  on  pins  riveted  into  the  corners 
of  the  yoke.  In  each  one  of  the  lower  ends  of  the  four 
pitmans  are  the  eccentric  adjusting  bushings  described  on 
p.  289  in  connection  with  the  small  machines.  The  lower 
ends  of  the  double-ended  cranks  carry  cross  connections 
to  the  lower  ends  of  the  cranks  on  the  opposite  shafts. 
The  two  sets  of  cranks  at  the  opposite  ends  of  the  machines 
are  at  right  angles  with  each  other,  thereby  transmitting 
a  perfect  rotary  motion  from  one  shaft  to  the  other.  The 
end  of  one  of  the  shafts  is  extended,  and  carries  a  lever 
by  which  the  pattern  is  lowered  and  raised.  A  special 
feature  is  the  coiled  compression  springs,  two  or  more  in 


292  PRACTICAL  IRON  FOUNDING 

number,  by  which  the  weight  of  the  yoke  and  its  burden 
is  counterbalanced,  so  that  patterns  are  drawn  and  raised 
easily.  Springs  of  different  strengths  can  be  substituted 
in  the  sockets  provided  for  them,  to  permit  of  exact  ad- 
justments for  patterns  of  different  weights. 

Square  machines  of  this  class  are  built  in  dimensions 
ranging  from  18  in.  upwards  to  60  in.  wide  and  120  in. 
long,  with  draws  of  from  6  in.  to  8  in.  They  are  built  low 
to  take  deep  flasks.  Bound  machines  are  also  made  with 
double  shafts,  with  deep  draws,  in  capacities  ranging 
from  24  in.  up  to  large  sizes;  60  in.  is  a  large  standard 
size,  but  larger  ones  are  built  when  required. 


EKi 


FIG.  202. — BABBITT-LINED  STRIPPING  PLATES. 

The  babbitt  lining  of  the  stripping  plates  in  Fig.  202 
will  be  observed.  The  practice  of  using  stripping  plates 
is  generally  open  to  the  objection  of  being  costly,  when 
the  openings  are  tooled  or  filed  to  make  a  close  fit  with 
the  bounding  edges  of  the  patterns.  The  babbitt  system 
dispenses  with  this  labour  in  the  following  way  (the  only 
exception  is  circular  openings  which  can  be  turned 
readily) : 

The  stripping  plate  is  cast  with  an  opening  about  |-  in. 
larger  all  round  than  the  patterns.  Its  upper  edge  is 
recessed  to  a  width  of  -J-  in.  and  depth  of  £  in.,  and  small 
holes  are  drilled  at  distances  of  about  -J  in.  apart,  into 
which  wire  nails  are  driven,  leaving  the  heads  about  fV  hi. 
below  the  intended  surface  of  the  babbitt.  When  the 


EXAMPLES  OF  MOULDING  MACHINES      293 

pattern  plate  is  placed  on  the  machine,  with  the  stripping 
plate  surrounding  it,  asbestos  string  is  laid  around  the 
pattern,  and  between  the  opening  in  the  stripping  plate 
and  the  backing  or  filling-down  thickness  pieces  on  the 
pattern  joint.  A  layer  of  putty  is  laid  round  to  form  a 
trough.  All  is  then  warmed,  and  babbitt  is  poured  in 
around  the  pattern,  filling  up  the  space.  Before  this  has 
quite  cooled,  the  operating  lever  is  pulled,  and  the  pattern 
drawn  down  through  the  babbitt.  The  surplus  is  then 
cut  away  from  the  surface  of  the  stripping  plate.  If  the 
babbitt  is  found  to  make  too  tight  a  fit  around  the  pattern, 
it  is  trimmed  off  until  the  pattern  moves  through  freely. 
From  50,000  to  150,000  moulds  can  be  made  before  a 
plate  requires  to  be  re-babbitted.  By  the  adoption  of  this 
cheap  and  ready  way  the  objection  to  stripping  plates  no 
longer  holds  good. 

In  fitting  these  up,  a  single  plate  is  thus  prepared 
before  the  second  is  taken  in  hand.  The  second  stage  is 
as  follows: 

Pattern  plates  and  stripping  plates  are  prepared  for 
the  complementary  portion  similarly  to  the  first,  and 
placed  on  a  moulding  machine  adjacent,  but  without  as 
yet  having  dowell  holes  drilled,  or  the  babbitting  done. 
But  the  pin  holes  are  drilled  in  the  lugs,  and  so  the 
stripping  plate  first  formed  is  taken  from  its  machine 
and  turned  over  and  placed  on  the  second  stripping 
plate — located  by  the  pins.  The  first  stripping  plate  thus 
locates  the  position  of  the  second  part,  which  is  now, 
therefore,  dowelled  in  place,  and  the  stripping  plate  No.  1 
put  back  on  its  own  machine.  The  plate  No.  2  is  now 
babbitted  round  its  portion  of  the  pattern.  Two  pat- 
tern plates  are  thus  prepared  with  strippers,  to  mould 
on  separate  machines  for  cope  and  drag  respectively, 


294  PRACTICAL  IRON  FOUNDING 

and  which  will  match  perfectly  when  the  moulds  are 
closed. 

The  question  often  arises  about  making  provision  for 
moulds  with  irregular  joint  faces.  Generally  the  method 
adopted  is  to  cast  pattern  and  plates  in  one,  in  a  mould 
rammed  originally  with  cope  and  drag  face  to  face,  and 
then  separated  by  the  intended  thickness  of  the  plate, 
and  poured,  after  a  suitable  frame  has  been  rammed 
around  the  mould.  In  the  Pridmore  system  this  is 
avoided  by  fastening  pieces  on  one  plate  to  stand  up  and 
come  to  the  raised  pattern  joint,  and  to  cast  pockets  in 
the  other  plate  which  are  approximately  the  reverse  of 
the  raising  pieces,  and  deeper.  Nails  are  driven  into  holes 
drilled  about  -J  in.  apart  over  the  surface.  The  plates  are 
then  placed  together  and  babbitt  poured  in,  so  forming 
an  exact  reverse. 

Rockover  Machines. — One  of  these  is  shown  at  the  left- 
hand  side  of  Fig.  197,  Plate  IX.  These  are  used  for  pat- 
terns in  which  there  is  sufficient  draught  to  permit  of  the 
lowering  of  the  mould  from  the  pattern,  assisted  frequently 
by  a  vibrator  rapping  action.  Often  they  are  used  in  con- 
junction with  a  stripper  plate  machine  making  one  portion 
of  the  mould.  The  action  of  the  machine  is  as  follows :  The 
pattern  plate,  being  covered  with  its  flask,  is  rammed  by 
hand  when  carried  on  one  side  of  the  machine.  The 
superfluous  sand  is  strickled  off  and  a  bottom  board  laid 
on  the  surface  and  clamped.  Then  the  plate  with  its 
flask  and  board  is  rocked  over  on  its  pivots  to  the  other 
side  of  the  centre  of  the  machine,  and  the  bottom  board 
deposited  on  a  stand  by  means  of  a  lever,  the  labour 
being  rendered  easy  by  the  counterbalancing  action  of 
coiled  springs.  The  mould  is  dropped  from  the  pattern 
and  the  latter  is  returned  to  its  original  position  to  be 


EXAMPLES  OF  MOULDING  MACHINES      295 

re-rammed.  The  varying  depths  of  boxes  are  provided  for 
by  adjustments  in  the  height  of  the  stand.  Some  machines 
have  provisions  for  self  adjustments  by  means  of  four 
depressible  pins  to  accommodate  unevennesses  in  bottom 
boards  and  differences  in  thickness  of  sand. 

Portable  Machines. — The  Farwell  moulding  machines, 
manufactured  by  the  Adams  Company,  of  Dubuque,  Iowa, 
are  built  in  two  broad  types  to  accommodate  work  lifted 
with  or  without  stripping  plates,  and  in  both  fixed  and 
portable  designs,  and  some  have  turret  heads  for  multiple 
and  other  moulding.  All  the  Farwell  machines  are  of 
the  presser  type,  and  are  all  hand  operated.  That  is,  no 
hand  ramming  is  done,  but  the  moulds  are  pressed,  and 
the  patterns  delivered  by  hand  levers. 

The  general  construction  of  the  ordinary  machine  is 
as  follows  (Fig.  203,  Plate  X):  Two  standards  support 
the  superstructure.  In  the  fixed  machines  these  terminate 
in  feet,  to  be  bolted  down  upon  timbers.  In  the  portable 
shown,  they  are  divided  and  spread  out  to  receive  the  pins- 
upon  which  plain  wheels  run.  On  the  top  of  the  stand- 
ards a  longitudinal  is  bolted,  carrying  a  table  consisting 
of  crossbars,  or  an  open  frame  upon  which  the  cleats  or 
battens  of  the  bottom  board  rest.  The  table  is  a  rigid 
fixture.  Above  is  the  presser  head — a  planed  casting 
carried  at  the  ends  of  pitmans  which  are  screwed  along 
for  a  considerable  length  from  the  ends  to  permit  of  a 
wide  range  of  adjustment  of  the  presser  head  for  height. 
The  head  can  be  thrown  back  out  of  the  way,  or  brought 
into  a  horizontal  position  over  the  table  and  mould  by 
the  left  hand.  Then  the  lever  to  the  right  is  pulled 
over,  the  attendant  pressing  his  weight  on  it,  so  com- 
pressing the  mould.  The  lever  is  in  the  horizontal  posi- 
tion when  the  man's  greatest  effort  is  being  exercised 


296  PRACTICAL  IRON  FOUNDING 

upon  it,  which  is  more  favourable  for  obtaining  the 
maximum  result  than  a  vertical  or  nearly  vertical  one 
would  be. 

This  is  a  simple  machine — termed  the  moulding  press 
— designed  for  work  that  requires  no  stripper  plate.  In 
this,  as  in  others  having  no  turn-over  table,  the  cope  and 
drag  are  pressed  by  the  turning  over  method,  or  else 
rammed  simultaneously  or  independent  of  each  other  on 
the  same  or  on  separate  machines.  The  operation  of 
moulding  is  briefly  this : 

Taking  first  a  pattern  requiring  a  plain  top :  A  match, 
which  may  be  either  a  bottom  board,  as  we  should  call  it, 
or  an  oddside,  is  placed  with  its  pattern  or  patterns  in 
position  on  the  table.  The  drag  or  bottom  box  is  laid 
over  it.  Facing,  and  then  box-filling  sand  are  riddled  and 
shovelled  in  and  struck  off  level.  A  bottom  board  used 
for  pressing  is  laid  on  the  sand.  One  movement  of  the 
lever  brings  the  top  forward  and  presses  the  mould.  The 
drag  is  now  turned  over  on  the  table,  occupying  ap- 
proximately the  same  position  centrally;  the  match  is 
removed  and  put  aside,  leaving  the  pattern  or  patterns 
embedded.  Parting  sand  is  strewn  and  the  cope  laid  in 
place,  facing  sand  riddled  in,  followed  by  the  box  filling, 
and  strickled  off,  a  presser  board  laid  on,  which  is 
identical  with  the  bottom  board  in  function  and  in  shape, 
with  a  trifling  difference  in  the  cleats  or  battens,  which 
are  hollowed  out  at  the  sides  so  as  to  be  easily  grasped. 
This  completes  the  moulding. 

The  sprue  cutting,  the  rapping,  and  lifting  out  of  the 
pattern  are  all  done  by  hand,  as  in  ordinary  work,  so 
that  the  saving  of  time  by  the  machine  is  due  to  the 
consolidation  of  the  sand  by  the  presser  instead  of  by 
Jiand.  The  precautions  adopted  to  ensure  the  proper 


EXAMPLES  OF  MOULDING  MACHINES      297 

degree  of  pressure  over  all  areas  will  be  noted  presently, 
and  also  the  withdrawal  of  deep  patterns  used  with  a 
stripper  plate. 

In  the  plain  moulding  press  to  which  these  remarks 
have  reference  patterns  are  also  used,  the  halves  or  por- 
tions of  which  go  on  opposite  sides  of  one  plate.  In  these 
cases  the  plan  adopted  is  this :  the  operation  proceeds  as 
in  the  previous  case  until  the  drag  part  is  laid  upon  the 
bottom  board  and  filled  with  sand  over  the  pattern.  In- 
stead, now,  of  pressing  the  board  down,  the  drag  part 
with  the  board  is  turned  over  and  the  cope  laid  on  and 
filled,  and  the  presser  board  laid  in  position.  The  presser 
head  is  now  pulled  down  on  the  presser  board,  and  the 
cope  and  drag  sand  are  thus  pressed  at  once  between  the 
top  and  the  bottom  boards. 

The  Farwell  universal  moulding  machine,  Fig.  204, 
Plate  X,  is  more  complete  than  the  moulding  press.  It 
can  be  used  either  for  shallow  patterns,  or  for  deep  ones, 
with  a  stripping  plate,  and  the  lift  is  mechanical.  In  the 
choice  of  fixed  or  portable  mounting  it  is  similar  to  that 
just  described.  But  the  universal  machine  is  fitted  with 
mechanism  for  lifting  the  pattern  or  patterns  from  above 
the  stationary  table.  The  patterns  are  mounted  on  a 
movable  table,  which  is  supported  by  a  long  slide  of 
hexagonal  section,  with  provision  for  taking  up  wear. 
The  machine  combines  a  common  moulding  press,  with 
a  stripping  plate,  so  that  either  can  be  used  at  will.  The 
construction  is  this: 

For  moulding  with  stripping  plates,  the  patterns  are 
secured  to  one  side  of  a  board  or  plate,  which  is  sup- 
ported a  little  way  above  the  stationary  press  table.  Only 
one  side  of  the  plate  is  utilized,  because  the  table  is  not  of 
the  turn-over  type.  Cope  and  drag  are  therefore  rammed 


298  PRACTICAL  IRON  FOUNDING 

on  different  machines,  or  on  a  long  machine  capable 
of  dealing  with  both  boxes  side  by  side  at  one  operation. 
The  pattern  plate  is  fitted  with  tabes  near  the  edges, 
through  which  loose  studs  pass  and  rest  upon  the 
movable  table,  termed  the  lift  table.  When  a  lever  at  the 
side  of  the  machine — the  lift  lever — within  reach  of  the 
operator's  left  hand,  is  raised,  these  studs  engage  with 
the  edge  of  the  flask  and  lift  the  mould  off  the  pattern 
plate.  The  sand  is  loosened  during  the  lift  by  the  right 
hand  of  the  attendant,  who  strikes  a  rapping  bar  hori- 
zontally between  two  projections.  The  box  is  then  taken 
off  and  laid  where  required  for  coring  or  pouring.  This 
is  an  arrangement  suitable  for  a  large  volume  of  work 
which  is  either  shallow,  or,  if  deep,  well  tapered,  or  of 
circular  section.  The  lift  is  truly  vertical,  while  the  rap- 
ping given  is  as  efficient  as  that  imparted  in  a  common 
mould,  but  less  in  amount — less  being  necessary  because 
the  machine  lifts  perfectly  vertical. 

When  deep  work  with  little  or  no  taper,  which  requires 
a  stripping  plate,  is  to  be  moulded,  the  pattern  plate  or 
frame  rests  upon  the  stationary  press  table.  The  strip- 
ping plate  lies  on  the  pattern  plate.  Three  or  four  studs 
attached  to  the  stripping  plate  come  down  and  rest  upon 
the  lift  table.  They  engage  with  guides  on  the  pattern 
plate,  and  control  the  vertical  movement  of  the  stripping 
plate.  By  raising  the  lift  lever  both  the  stripping  plate 
and  mould  are  lifted  off  the  pattern,  after  which  they 
are  taken  away. 

This  is  a  concise  account  of  these  machines,  without 
dwelling  much  on  minute  details.  Some  of  these  must 
now  be  noted,  and  the  first  matter  which  a  moulder 
would  like  to  be  informed  about  is  the  pressing  opera- 
tion, by  which  hand  ramming  is  wholly  dispensed  with. 


EXAMPLES  OF  MOULDING  MACHINES      299 

In  shallow  work  the  Farwell  press  simply  utilizes  the 
presser  head  coming  down  on  the  plain  presser  board  for 
the  consolidation  of  the  sand.  But  in  deeper  patterns 
two  further  devices  are  utilized.  One  is  peining,  the 
equivalent  of  our  pegging  of  sand  down  the  deeper  sides 
of  patterns  before  ramming  over  the  upper  surfaces; 
the  other  is  the  device  of  cutting  out  the  presser  board  to 
the  approximate  outlines  of  the  patterns  to  be  rammed. 

Peining  is  done  by  tacking  a  strip  of  wood  of  about 
•J-  in.  square  on  the  faces  of  both  bottom  and  presser 
boards,  close  alongside  the  edges.  These,  of  course,  being 
thrust  into  the  mould  before  the  flat  portion  of  the 
board  comes  into  operation,  consolidate  the  sand  firmly 
round  the  edges  of  the  pattern  and  against  the  box  sides 
adjacent,  just  as  would  be  done  by  the  moulder's  pegging 
rammer. 

The  presser  head,  which  is  cut  to  conform  to  the  shape 
of  the  patterns,  is  attached  to  the  presser  top  of  the 
machine.  The  expense  of  cutting  it  out  is  not  so  objec- 
tionable as  might  appear,  It  is  a  question  of  number  of 
moulds  wanted.  One  would  hardly  cut  it  for  a  few 
moulds,  but  it  would  generally  pay  for  a  score  or  two, 
while  when  the  cost  is  distributed  over  hundreds  it  is  a 
mere  trifle  on  each.  The  expense  is  not  so  great  as  that 
of  cutting  out  half  a  core  box,  which  it  resembles,  because 
the  accuracy  necessary  in  a  core  box  is  not  required  for 
pressing  the  sand. 

When  the  Adams  Company  plate  patterns  they  use 
saw-blade  steel  plates  r3¥  in.  thick,  which  are  straight- 
ened, ground,  and  polished  on  one  side.  As  the  patterns 
are  only  mounted  on  one  side,  the  plates  are  stiffened  by 
riveting  three  bars  £  in.  by  1-J-  in.  on  the  underside,  and 
running  in  the  longitudinal  direction.  The  patterns  are 


300  PRACTICAL  IRON  FOUNDING 

of  metal,  secured  to  the  polished  face.  Sockets  of  gas- 
pipe,  previously  mentioned,  are  fitted  near  the  edges  of 
the  plates  to  receive  the  loose  pins,  which  have  been 
described  as  coming  down  and  resting  on  the  lift  table 
of  the  machine.  When  patterns  of  wood  are  used,  they 
are  secured  to  one  side  of  a  board. 

As  the  pattern  plate  stands  up  on  its  pins  away  from 
the  lift  table,  curved  patterns  and  curved  stripping  plates 
are  easily  fitted. 

For  more  rapid  production,  pattern  plates  are  dupli- 
cated on  the  same  machine,  so  that  one  man  will  ram 
cope  and  drag  simultaneously.  The  pattern  or  patterns 
are  set  by  centre  lines  to  right  and  left  of  the  common 
centre  dividing  the  cope  from  the  drag  portion;  or  two 
machines  are  employed.  In  plain  cored  work  a  boy  may 
then  set  the  cores. 

Moulding  boxes  are  not  necessarily  made  to  fit  these 
machines,  as  they  simply  lie  upon  the  table,  and  the 
stripping  plates,  when  such  are  used,  can  be  adapted  to 
the  boxes.  But  there  are  certain  relations  between  boxes 
and  bottom  or  presser  boards  which  should  be  regarded 
if  the  best  economy  is  studied.  The  boards  and  boxes  and 
the  depths  of  patterns  should  be  mutually  related.  As 
the  bottom  and  presser  boards  enter  the  drag  and  cope 
to  press  the  sand,  £  in.  is  the  allowance  in  depth  made 
for  this,  so  that  whatever  the  depth  of  flasks  required 
for  hand  moulding,  -£-  in.  must  be  added  for  machine 
moulding.  The  differences  in  depth  of  flasks  for  different 
jobs  are  recommended  to  be  made  in  these  boards  and 
in  the  match.  Thus,  taking  9^  in.  as  a  convenient 
distance  between  the  table  and  top,  when  the  pressing 
lever  is  about  horizontal  the  machine  should  be  adjusted 
to  that,  and  shallower  flasks  fitted  by  increasing  the 


EXAMPLES  OF  MOULDING  MACHINES      301 

thickness  of  the  cleats  of  the  boards  and  the  match. 
The  bottom  and  presser  boards  are  made  smaller  by 
I  in.  than  the  inside  of  the  flasks,  so  that  they  enter 
easily  when  pressed.  They  are  of  white  pine  1J  in.  and 
1  [  in.  thick  respectively,  with  battens  4  in.  by  1£  in.  The 
battens  of  the  top  or  presser  board  are  hollowed  out  for 
the  hands. 

Ordinary  flasks  of  wood,  or  iron,  or  snap  flasks  are  em- 
ployed. A  cherry  snap  flask  is  made  by  the  Adams  Com- 
pany, protected  with  iron  on  the  top  edges,  grooved  in- 
side to  hold  the  sand,  with  pins  of  triangular  section. 

A  special  Farwell  machine  is  fitted  with  a  turret  head 
for  the  production  of  multiple  moulds.  It  is  an  ordinary 
moulding  press  fitted  with  a  head  having  two  portions. 
On  one  portion  a  pattern  plate  containing  a  part  of  a 
mould  is  attached.  On  the  other  a  peining  or  pegging 
frame  is  secured,  the  object  of  which,  as  previously  ex- 
plained, is  to  consolidate  the  sand  around  the  edges 
preparatory  to  the  surface  pressing.  A  flask  filled  with 
loose  sand  is  laid  on  the  table  over  the  second  portion  of 
the  pattern,  and  the  peining  frame  brought  down  upon 
it.  The  surplus  sand  is  strickled  off  and  a  thin  layer  of 
facing  sand  riddled  over.  Into  this  the  pattern  or  the 
patterns  on  the  turret  are  pressed,  so  forming  a  portion 
of  a  mould  on  each  face  of  the  sand  mould.  The  first  sec- 
tion is  placed  on  the  floor,  and  the  others  are  piled  on 
as  made  until  completed. 

Fig.  205,  Plate  XI,  shows  a  hand  machine  with  non- 
turn-over  table,  and  hinged  presser-head,  by  the  Berk- 
shire Manufacturing  Company,  of  Cleveland,  Ohio.  The 
pressure  is  intensified  by  toggle  levers.  The  pattern- 
plate  is  lifted  from  the  drag,  and  the  cope  from  the  plate 
simultaneously  by  the  movement  of  the  lever  seen  below, 


302  PRACTICAL  IRON  FOUNDING 

the  guidance  taking  place  through  four  posts,  a  pneu- 
matic vibrator  put  into  action  by  the  knee  assisting  the 
delivery.  The  posts  are  attached  to  a  frame  which  per- 
mits of  adjusting  their  position  to  suit  different  pattern 
plates  and  boxes.  The  frame  is  operated  by  gears  run- 
ning inside  racks  ensuring  a  straight  lift,  and  the  frame 
is  also  coerced  in  guides.  Canvas  guards  enclose  the 
vital  parts.  Copes  and  drags  are  rammed  on  the  two 
sides  of  a  plate,  or  on  different  machines. 

Tabor  Machines. — The  Tabor  Manufacturing  Company, 
of  Philadelphia,  make  moulding  machines  to  suit  the 
varied  classes  of  work  required  in  foundries,  some  for 
stripping  plates,  some  without,  some  for  hand,  and  others 
for  power  ramming.  Improvements  are  effected  from  time 
to  time  in  the  standard  types,  besides  which  special 
adaptations  are  constantly  being  made  to  suit  special 
classes  of  work  and  existing  moulding  boxes.  For  these 
reasons  it  is  not  possible  to  take  any  one  machine  and 
describe  it  as  being  a  Tabor.  It  would  only  be  correct  to 
say  so  respecting  certain  main  elements  in  the  design  and 
some  fundamental  details.  For  this  reason  the  firm  is  un- 
willing to  have  these  machines  described  in  any  other 
than  a  general  way,  lest  an  idea  should  be  conveyed  that 
the  illustration  which  might  be  given  would  represent  a 
hard-and-fast  design.  We  shall  therefore  only  attempt 
to  deal  with  the  broad  features  which  characterize  these 
machines,  illustrating  one  only,  the  10-inch  power 
squeezer  for  light  work  (Fig.  206,  Plate  XI). 

An  observer  would  notice  the  vibrating  action  through 
which  the  pattern  is  loosened  from  the  sand  previous  to 
its  withdrawal,  as  being  one  of  the  cardinal  features  of 
many  of  the  Tabor  machines.  It  does  not  dispense  with 
other  devices,  but  it  renders  possible  a  good  deal  of  work 


EXAMPLES  OF  MOULDING  MACHINES      303 

which  could  not  be  accomplished  by  any  other  means, 
short  of  an  expensive  rig-up  of  stripping  plates.  The 
vibrator  is  a  plunger  from  f  in.  to  2  in.  diameter,  ac- 
cording to  requirements,  which  plays  to  and  fro  under 
the  action  of  compressed  air  at  a  pressure  of  about  75  Ib. 
per  square  inch,  brought  through  a  hose  and  actuated 
by  the  attendant  pushing  a  valve.  The  vibrator  moves 
to  and  fro  several  thousand  times  in  a  minute,  and 
strikes  against  hardened  anvils  at  each  end  of  its  cylinder. 
The  result  is  that  the  pattern  is  shaken  at  an  extremely 
rapid  rate  with  a  much  slighter  degree  of  movement  than 
that  which  is  imparted  in  ordinary  rapping.  It  is  so 
slight  that  when  a  deep  pattern  is  returned  into  the 
sand,  it  has  to  be  rapped  again  before  it  can  be  with- 
drawn. The  result  is  therefore  the  same  as  though  an 
expensive  stripping  plate  were  used.  In  the  vibrator 
frame  machines,  one  vibrator  frame  is  fitted  to  any  single 
machine,  but  to  that  any  patterns,  large  or  small,  are 
readily  fitted.  The  frame  is  an  open  one,  slotted  around 
its  inner  edges  to  receive  extensions  from  the  pattern 
placed  within  the  frame.  The  extensions,  being  thin,  are 
sometimes  attached  to  gates,  and  frequently  to  core 
prints.  In  the  latter  case  they  are  utilized  also  as  vents 
going  to  the  outside  of  the  mould.  Pins  or  screws  connect 
the  extension  pieces  to  the  vibrator  frame.  Some  firms 
keep  a  standard  or  jig  frame  in  the  pattern  shop  to 
facilitate  the  fitting  of  any  patterns  to  the  vibrator 
within  the  capacity  of  the  machine. 

The  vibrator  frame  is  guided  in  flasks  by  three-cornered 
pins,  one  at  each  end.  These  fit  within  the  pins  of  the 
drag,  which  are  also,  of  course,  of  triangular  form,  while 
triangular  guides  on  the  cope  fit  outside  these  pins. 

We   will   now   observe   the   operation    of  the   Tabor 


304  PRACTICAL  IRON  FOUNDING 

• 

machine  (Fig.  206,  Plate  XI),  and  the  first  thing  to  note 
is  the  absence  of  the  turn-over  table  which  is  embodied  in 
numerous  machines.  This  is  an  advantage  in  one  respect, 
that  unjointed  patterns  may  be  employed,  which  is  im- 
practicable on  turn-over  tables.  No  special  fitting  of  boxes 
to  plates  or  tables  is  required,  but  the  boxes  fit  to  the 
vibrator  frames  and  to  each  other.  Being  able  to  take 
any  unjointed  pattern  of  wood  or  metal  and  fit  it  within 
the  vibrator  frame,  Fig.  207,  Plate  XII,  and  mould  it  by 
turning  or  rolling  it  over,  is  a  great  point  in  favour  of  a 
machine.  It  would,  of  course,  weigh  more  in  the  case  of 
moulds  of  which  a  small  number  only  were  wanted  than 
in  the  case  of  those  where  hundreds  or  thousands  were 
required,  because  the  latter  will  pay  for  the  jointing  of 
patterns  and  their  careful  fitting.  Another  point  in  favour 
of  the  moulding  of  unjointed  patterns  is  that  it  is  easier 
to  ensure  absence  of  overlap  and  fin  than  when  they  are 
jointed,  especially  when  put  on  separate  plates.  Even 
though  they  match  originally,  the  wear  and  tear  of 
machines,  of  pattern,  and  of  stripping  plates,  when  such 
are  used,  tends  to  increasing  departure  from  perfect  joint- 
ing of  moulds. 

Having  the  pattern  mounted  within  the  vibrator  frame, 
the  sequence  of  operations  is  as  follows:  The  joint  board 
is  laid  upon  the  table,  and  the  pattern  or  patterns  con- 
tained within  the  vibrator  frame  are  placed  on  it.  The 
drag  or  bottom  box  is  laid  on,  fitting  it  by  its  hollow 
vee-shaped  pins  over  the  pins  at  the  ends  of  the  vibrator 
frame.  Sand  is  shovelled  into  the  box  and  struck  off 
level,  and  a  bottom  board  with  thick  cleats  or  battens 
laid  on  the  sand.  Above  this  there  is  a  presser  head, 
hitherto  thrown  back  clear  of  the  work  by  hinged  rods  at 
the  sides,  but  now  pulled  forward  until  the  presser  board 


PLATE  XIV 


Fadnqp.  304 


FIG.  213.— PATTERNS,  CORE  BOXES,  AND  MULTIPLE  CASTINGS. 
THE  LONDON  EMERY  WORKS  Co. 


EXAMPLES  OF  MOULDING  MACHINES      305 

stands  horizontally,  in  which  position  it  is  arrested  by 
stops.  There  is  a  three-way  cock  at  the  side  of  the 
machine  by  which  the  attendant  admits  compressed  air 
at  from  60  Ib.  to  80  Ib.  pressure,  into  the  inverted 
cylinder  in  the  base  of  the  machine,  forcing  the  match 
board,  drag,  and  bottom  board  up  against  the  presser 
head  once,  twice,  or  thrice,  as  happens  to  be  most  suit- 
able for  the  work  in  hand.  This  completes  the  first 
stage. 

The  ramming  head  is  next  thrown  backwards,  and  the 
drag,  with  its  joint  board,  turned  over,  with  the  vibrator 
frame  between  them.  The  match  is  then  lifted  off, 
leaving  the  joint  face  open  to  receive  the  top  box,  which 
is  fitted  over  the  pins  of  the  bottom  box.  Parting  sand  is 
dusted  over  the  face,  moulding  sand  thrown  on,  a  board 
placed  over,  the  presser  head  pulled  forward,  the  cock 
turned,  and  the  mould  pressed  up  against  the  head. 
This  completes  the  second  stage. 

Delivery  of  the  pattern  is  effected  as  follows :  The  cope 
is  first  lifted  by  hand.  As  it  is  about  to  be  lifted  the  at- 
tendant pushes  a  hinged  pad  in  front  of  the  machine 
with  his  left  knee,  which  admits  air  to  the  vibrator,  and 
during  its  action  he  lifts  the  cope  off.  To  withdraw  the 
patterns  from  the  bottom  box  the  vibrator  is  started,  and 
the  frame  is  lifted  by  the  handles  at  the  ends. 

On  first  thought  we  might  be  disposed  to  think  that 
one  of  the  chief  advantages  of  a  moulding  machine,  that 
of  a  perfectly  vertical  lift,  is  sacrificed.  The  importance  of 
this  is  greater  in  the  top  than  in  the  bottom.  But  the 
drag  pin  is  sufficiently  long  to  ensure  perfect  control  of 
the  lift  in  moulds  of  medium  depth  at  least,  so  that  un- 
less in  work  which  is  obviously  suitable  for  stripper 
plates  the  supposed  objection  does  not  apply,  and  in 

x 


306  PRACTICAL  IRON  FOUNDING 

some  deep  stripper-plate  work  the  vibrator  is  included 
with  advantage. 

Tabor  machines  are  fitted  with  stripping  plates  of  sheet 
metal  when  required,  and  with  the  devices  termed  stools. 
The  sheet  metal  covers  the  entire  surface  of  the  machine, 
except,  of  course,  where  it  is  cut  out  round  the  patterns. 
The  sheet  is  supported  by  the  pattern  plate  during  ram- 
ming, and  the  stools  carry  its  edges  during  the  with- 
drawal of  the  pattern.  The  stools  in  this  case  are  loose 
cylinders  of  metal  which  fit  in  round  holes  bored  through 
the  pattern  plate.  The  surfaces  of  their  upper  ends 
come  flush  with  the  surface  of  the  plate,  and  their  lower 
ends  rest  on  a  stool  plate.  This  last  is  supported  rigidly 
by  means  of  brackets  from  the  frame  which  carries  the 
moulding  boxes,  so  that  it  has  the  same  upward  motion 
as  the  boxes,  and  the  upper  ends  of  the  stools  therefore 
remain  in  contact  with  the  sand  of  the  mould  until  it  is 
lifted  from  the  machine. 

Machines  made  by  the  Baden  Engineering  Works  of 
Durlach  embrace  nearly  every  type.  Some  are  of  small 
size;  others  are  of  very  large  dimensions;  they  in- 
clude numerous  designs  and  systems,  embracing  hand, 
hydraulic,  and  pneumatic  operation,  turn-over  plates, 
and  fixed  plates,  pulley  moulding,  and  other  special 
machines  for  pipes,  firebars,  toothed  wheels,  etc. 

The  simplest  type  of  hand  machine  made  is  of  very 
plain  design.  It  consists  of  a  table  supported  on  four 
stiff  legs,  which  bring  it  to  a  height  suitable  for  ramming 
by  a  man  standing  upright.  The  pattern  plate  is  fastened 
on  the  table,  and  the  moulding  box  placed  over  it,  fitting 
by  its  pins  thereto.  The  sand  is  rammed  and  strickled 
level,  and  the  box  lifted  off  the  pattern  truly  by  a  pedal 
lever  arrangement,  which  lifts  a  crosshead  underneath, 


EXAMPLES  OF  MOULDING  MACHINES      307 

when  four  rods  at  each  corner  that  pass  through  the 
pattern  plate  push  up  the  box  clear  of  the  pins.  These 
machines  are  made  for  boxes  that  range  from  12  in.  to 
24  in.  square,  and  are  intended  to  be  used  in  pairs  for 
top  and  bottom  boxes  respectively. 

Another  single-lift  machine  without  a  turn-over  plate  is 
designed  for  boxes  of  larger  dimensions.  Instead  of  the 
box  being  lifted  off,  which  could  not  be  readily  done  be- 
cause of  its  weight  and  size,  the  pattern  is  drawn  down- 
wards by  means  of  a  lever  actuated  by  a  screw  of  quick 
pitch,  the  weight  of  the  pattern  table  being  counter- 
balanced. The  box  is  left  supported  on  four  projections 
on  the  frame.  This  machine  is  suitable  for  patterns  of 
no  great  depth.  In  deep  work  it  is  better  to  lift  the 
pattern  upwards  out  of  the  sand  than  to  draw  it  down- 
wards. 

Other  hand  moulding  machines  by  this  firm  have  a 
turn-over  plate  fitted,  the  pattern  parts  being  fastened  on 
opposite  sides  of  it;  patterns  of  plaster,  white  metal,  or 
other  materials  being  used  equally  well  with  those  of 
wood  or  metal.  When  preparing  these  pattern  plates  for 
foundries  which  deal  less  in  repetitive  work  than  in  small 
numbers  of  castings,  the  plates  are  made  with  a  large 
number  of  holes  which  are  fitted  with  corks  when  not  in 
use.  Holes  can  be  selected  from  these  to  suit  various 
patterns,  and  the  remainder  left  with  the  corks  in.  The 
method  of  fastening  is  by  means  of  tubes,  screws  from 
one  half  the  pattern  entering  into  holes  in  the  tubes  in  the 
other  half,  ensuring  the  correct  placing  of  the  two  portions 
through  the  intervening  plate.  The  halves  of  the  mould- 
ing boxes  are  placed  on  opposite  sides  of  the  plate,  their 
positions  being  fixed  by  two  pins  which  pass  through  the 
plate,  and  stand  out  on  opposite  sides,  and  to  which  the 


308 


PRACTICAL  IRON  FOUNDING 


box  lugs  are  secured  by  wedges.  Or,  the  pins  form  a  part 
of  the  box  and  pass  through  the  plate.  These  machines 
are  made  for  work  of  medium  dimensions,  taking  boxes 
ranging  from  16  in.  by  12  in.  to  40  in.  by  32  in.  The 


FIG.  208. — TURN-OVER  TABLE  MACHINE. 
FRONT  ELEVATION. 

depth  of  each  half-box  varies  from  10  in.  to  12  in.,  a  good 
depth  for  machine  moulding;  but  in  this  case,  of  course, 
the  pattern  plate  is  lifted  from  each  box  part. 

In  another  hand  machine  of  larger  dimensions,   in 
which  the  design  of  a  turn-over  table  is  retained,  the 


EXAMPLES  OF  MOULDING  MACHINES      309 


moulding  box  is  supported  on  a  carriage  running  on 
wheels,  and  is  lifted  up  to  the  pattern  plate  and  lowered 
therefrom  by  hydraulic  power.  A  piston  underneath  does 
the  lifting  and  lowering,  and  as  no  great  power  is  re- 
quired, a  hand  pump  can 
be  used  in  the  absence  of 
a  regular  hydraulic  plant. 
Boxes  of  larger  dimensions 
are  used  on  this  machine, 
ranging  up  to  172  in.  by 
16  in.,  with  a  depth  of  12  in. 
In  other  turn-over  types 
of  machines,  instead  of 
hand  -  ramming,  provision 
is  made  for  compressing 
the  sand.  In  one  of  these 
toggle  levers  are  employed 
to  permit  of  the  exercise 
of  increased  force  as  the 
depth  of  sand  increases. 
This  machine  is  illustrated 
by  the  drawings  Figs.  208 
and  209  in  part  elevations 
and  sections.  TwoA-shaped 
frames  /I,  A,  sustain  the 
mechanism.  Two  cross  FlG  209.-Tu^ovER  TABLE 
stretchers  B,  C  connect  the  MACHINE.  VERTICAL  SECTION. 
frames.  D,  E  are  the  levers 

which  form  the  toggle — straightening  out  as  the  pressure 
on  the  mould  is  increased.  They  are  pivoted  in  bosses  in 
C  above,  and  in  B  below,  and  are  actuated  by  the  hand 
lever  I  which  turns  the  pinion  P  engaging  in  the  quad- 
rant rack  E  on  the  lever  D.  The  table  F  is  thus  pressed 


310  PRACTICAL  IRON  FOUNDING 

upwards  against  the  moulding  boxes  Ky  K,  in  opposition 
to  the  crosshead  G,  which  is  connected  by  rods  H,  H  to 
the  bottom  of  the  standards.  G  is  pivoted  by  the  rods, 
and  can  be  swung  back  out  of  the  way  to  permit  of  the 
insertion  and  removal  of  boxes. 

The  turn-over  table  is  seen  at  J,  with  boxes  at  K,  K. 
J  carries  intermediate  blocks,  the  function  of  which  is  to 
receive  the  pins  for  the  boxes.  L  is  the  presser  board, 
and  M  a  loose  frame  into  which  the  surplus  sand  is 
shovelled,  of  a  thickness  about  equal  to  the  reduction 
effected  by  the  compression.  The  box  parts  are  secured 
to  the  table  while  being  turned  over  by  clamps,  one  of 
which  is  seen  broken  off  at  Ar.  Each  half  is  fitted  and 
compressed  separately,  turned  over,  the  cottars  knocked 
back,  the  box  part  received  by  the  table  F,  and  the  pat- 
tern plate  lifted  from  off  it  by  the  counterweighted  lever 
0,  the  crosshead  G  being  of  course  thrown  back  out  of 
the  way.  The  top  and  bottom  parts  of  the  mould  are 
thus  prepared  alternately  on  one  machine.  The  sequence 
is  as  follows: 

A  box  part  is  first  fastened  on  each  side  of  the  turn- 
over plate  on  which  the  patterns  are  set,  and  the  bottom 
box  being  first  turned  upwards,  is  filled  with  facing  and 
coarse  sands  up  to  the  top  of  the  clamping  frame  M,  the 
pressing  board  L  is  put  on,  the  head  G  brought  over  it, 
and  the  toggle  lever  /pulled.  The  turn-over  plate  is  next 
reversed,  bringing  the  box  just  pressed  down  on  the 
table,  and  the  other  or  top  box  is  treated  similarly.  Then 
the  wedges  of  the  bottom  box  are  knocked  back,  and  the 
plate  lifted  and  the  box  drawn  forward  on  the  table. 
The  plate  is  then  turned  over  for  another  box  part. 

Besides  these  there  are  large  numbers  of  machines  that 
are  operated  hydraulically,  ranging  from  some  of  very 


312  PRACTICAL  IRON  FOUNDING 

simple  type  for  small  castings,  and  attended  by  boys,  to 
others  of  very  large  dimensions  and  of  more  or  less  com- 
plexity. The  advantages  of  the  application  of  hydraulic 
power  to  this  class  of  work  are  indisputable.  The  stand- 
ard pressures  adopted  are  750  Ib.  to  the  square  inch  for 
moulds  for  iron  castings,  and  1,500  Ib.  for  those  of  steel 
and  other  castings.  As  the  sizes  of  boxes  increase,  the 
weight  of  the  box,  with  that  of  the  enclosed  sand,  taxes 
the  muscles  severely  in  hand  machines,  in  spite  of  long 
levers  and  counterweighting.  The  application  of  power 
does  away  with  this  exertion,  and  permits  of  the  use  of 
machines  of  any  dimensions  adapted  to  heavy  classes  of 
work  that  could  not  be  economically  put  on  hand-oper- 
ated machines.  The  hand  machines,  with  turn-over 
plates  just  now  described,  are  also  made  after  the  same 
model  for  hydraulic  power,  a  piston  beneath  pressing  the 
moulds  upwards  between  it  and  the  crosshead  at  the  top. 
Machines  of  this  type  range  from  a  capacity  for  boxes 
measuring  from  16  in.  by  12  in.  to  172  in.  by  16  in. 

Another  class  of  hydraulic  machine  is  double,  Fig.  210, 
without  a  turn-over  plate,  the  object  being  to  have  two  men 
working  on  top  and  bottom  of  a  mould  with  a  central 
presser.  The  moulding  tables  travel  to  and  from  the  press. 
The  moulds  are  prepared  on  these  tables,  and  brought 
under  the  press  in  turn.  The  pattern  plate  is  removed 
downwards  from  the  mould  after  pressing,  leaving  the 
moulding  box  on  two  side  bars.  The  largest  machines  are 
fitted  with  a  light  hydraulic  crane,  to  place  the  boxes  on 
the  closing-up  table.  In  the  largest  of  these  types,  boxes 
up  to  150  in.  by  16  in.  are  handled. 

The  Figs.  211,  Plate  XIII,  show  a  group  of  machines  by 
the  London  Emery  Works  Company,  for  moulding  flat 
and  shallow  castings,  such  as  gas,  water,  or  electric 


EXAMPLES  OF  MOULDING  MACHINES      313 

light  fittings,  stove  and  grate  parts.  The  two  machines, 
seen  at  the  right  hand,  each  comprise  a  pattern  plate, 
mounted  on  a  hydraulic  ram  enclosed  in  a  cast  iron  case 
to  prevent  the  intrusion  of  sand  and  dirt.  The  rammer 
head  is  supported  on  pivoted  links,  and  is  swung  back 
during  the  filling  of  the  moulding-box  with  sand,  and  it 
can  be  adjusted  to  regulate  the  length  of  stroke,  thus 
economizing  power.  The  moulding-box  is  lifted  off  the 
pattern  by  four  rods  actuated  by  the  lever  seen  in  front. 
These  rods  must  be  flush  with  the  pattern  plate  in  their 
lowest  position,  and  they  can  be  adjusted  to  suit  the 
various  heights  of  pattern  plates. 

It  is  advantageous  to  have  two  machines  working  to- 
gether as  shown,  one  making  the  bottom  and  the  other 
the  top  boxes,  as  the  work  can  then  be  carried  on  con- 
tinuously, otherwise  the  patterns  must  be  changed,  or 
arranged  on  the  reversible  pattern-plate  system.  If  re- 
quired, the  machine  can  be  constructed  for  extracting 
deep  patterns  through  a  stripping  plate.  Snap  flasks  can 
be  used.  Should  an  hydraulic  plant  be  unavailable  for 
any  reason,  the  machine  can  be  worked  by  hand  without 
any  alteration.  At  the  left  a  hydraulic  core  machine  is 
shown,  completing  the  installation. 

Messrs.  Bopp  and  Keuther,  of  Mannheim,  make  a 
speciality  of  hydraulic  moulding  machines  of  several 
types,  comprising  very  advanced  examples. 

A  hydraulic  machine  with  turn-over  table  is  shown  in 
vertical  section  in  Fig.  212.  The  table  A  swings  in  trun- 
nions, which  are  clamped  by  the  handles  a,  a  when  the 
table  is  set  in  its  horizontal  position.  The  trunnion  bear- 
ings are  in  one  with  the  sleeves  B,  B  that  slide  in  the  up- 
rights, and  the  height  of  which  is  set  by  the  collars  b,  b 
clamped  to  the  pillars.  At  the  commencement  of  working, 


314  PRACTICAL  IRON  FOUNDING 

an  empty  half-mouldingbox  is  set  on  the  turn-over  plate, 
and  the  other  half  on  a  wagon  C  that  runs  on  rails.  The 
upper  box  is  first  filled  with  sand,  and  the  regulating 
valve  D  operated,  causing  the  ram  to  move  upwards, 
pressing  the  sand  in  the  box  up  against  the  presser 
head  F.  The  latter  is  hinged,  to  be  flung  aside  during 
ramming.  A  pressing  frame  6r,  to  confine  the  loose  sand, 
is  laid  over  the  box,  as  is  usual  in  such  cases.  Before 
taking  off  the  pressure,  the  two  half-boxes  are  clamped 
together  against  the  intervening  plate,  the  clamps  being 
shown  at  c,  c.  The  regulating  valve  D  is  now  released, 
allowing  the  ram  to  sink  gently,  and  with  it  the  plate  A 
with  the  box  parts,  until  their  movement  is  arrested  by 
the  collars  b,  I.  The  plate  is  now  turned  over,  bringing 
the  rammed  box  underneath  and  the  unrammed  one  up- 
wards. The  latter  is  then  filled  with  sand,  and  pressed 
as  the  other  was.  The  clamps  are  next  released  and  the 
ram  lowered;  the  descent  is  arrested  by  the  collars  b,  b, 
and  the  second  box  sinks  away  from  the  pattern.  The 
process  is  thus  repeated,  successive  half  boxes  being 
rammed  on  opposite  sides  of  the  plate. 

It  is  customary  in  using  these  machines  to  press  the 
pattern  into  the  mould  after  blackening,  as  brass- 
founders  do.  Various  presser  heads  can  be  made  inter- 
changeable on  the  arms  to  suit  moulds  of  different 
depths.  These  machines  are  made  in  a  large  range  of  di- 
mensions. With  the  hydraulic  arrangement  very  heavy 
moulds  can  be  handled  with  great  facility. 

The  question  of  floor  space  often  arises  when  the 
adoption  of  moulding  machines  is  being  considered. 
Even  if  the  machines  themselves  do  not  occupy  much 
room,  much  space  is  required  for  the  finished  moulds, 
the  sand,  and  empty  moulding  boxes.  The  problem  be- 


EXAMPLES  OF  MOULDING  MACHINES      315 

comes  acute  in  proportion  to  the  rapidity  of  action  of  the 
machine.  One  solution  is  the  portable  machine,  p.  295. 
Another  solution  is  that  of  multiple  moulding.  Machines 
are  constructed  by  which  a  single  half  moulding  box,  after 
being  pressed  on  both  sides  carries  a  mould.  The  half 


FIG.  212. — HYDRAULIC  MACHINE  WITH  TURN-OVER  TABLE. 

boxes  are  then  stacked  on  top  of  each  other,  a  complete 
mould  being  formed  at  each  joint,  and  the  entire  stack  is 
poured  through  one  gate.  By  stacking  the  boxes  in  this 
manner  the  difficulty  of  floor  space  is  solved,  but  other 
important  advantages  result.  Thus,  as  each  half  mould- 
ing box  contains  two  half  moulds,  one  half  box  suffices 
for  each  complete  mould;  and  on  reference  to  the  illus- 


316  PRACTICAL  IRON  FOUNDING 

tration,  Fig.  213,  Plate  XIV,  it  is  shown  that  by  using  nine 
half  boxes  eight  piles  of  castings  are  obtained.  As  only 
the  upper  half  box  in  each  stack  contains  an  ingate,  a 
considerable  saving  of  metal  is  effected.  Also,  only  half 
the  quantity  of  sand  is  necessary  for  each  mould.  As, 
using  ordinary  machines,  two  half  boxes  are  required  for 
each  complete  mould,  the  capacity  of  the  multiple  machine 
is  therefore  nearly  doubled.  The  illustration  shows  pat- 
tern plates,  core  plates,  or  boxes,  some  cores,  and  a  pile  of 
castings  as  poured.  The  machines  used  are  practically 
identical  with  those  shown  in  Fig.  211,  Plate  XIII.  The 
moulding  box  is  lifted  off  the  pattern  on  four  pins  by  the 
lever  in  front  of  the  machine.  The  presser-head,  how- 
ever, which  carries  underneath  one-half  the  pattern,  does 
not  swing  back,  but  is  arranged  to  push  back  on  rollers. 

The  method  of  working  is  as  follows:  a  moulding  box 
is  placed  on  the  pattern  plate,  a  sand  frame  placed  on  it 
and  filled  with  sand.  The  presser-head  with  pattern  plate 
is  then  drawn  over  and  the  box  rammed  in  the  usual 
manner.  A  half-mould  is  thus  made  on  each  side  of  the 
half  box.  After  pushing  the  presser-head  back,  the 
moulding  box  is  raised  off  the  pattern  plate  on  four 
pins  by  a  lever  in  front  of  the  machine.  Continuing  in 
this  way  one  box  after  the  other  is  made  and  stacked 
in  lots  of  ten  to  twelve,  the  top  one  being  weighted  as 
usual. 

A  machine  designed  for  multiple  moulding,  by  Messrs. 
Bopp  and  Keuther,  is  shown  in  Figs.  214,  215,  in  which 
two  half-moulds  are  made  at  one  pressing.  One  half  is 
done  in  the  usual  way  by  a  half-pattern  A,  on  a  plate; 
the  other  half  is  by  a  frame  B,  which  is  pressed  into  the 
upper  half  of  the  moulding  box  C.  The  relations  of  the 
moulds  and  patterns  plate  before  pressing  are  shown  in 


EXAMPLES  OF  MOULDING  MACHINES      317 

Fig.  214,  and  after  pressing  in  Fig.  215.   The  method  of 
operation  is  as  follows : 

The  box  part  C  is  carried  upon  a  frame  D,  which  is 
slid  by  means  of  sockets  upon  vertical  guides.  When  set 


Fm.  214.  FIG.  215. 

MACHINE  FOR  MULTIPLE  MOULDING. 

thus  in  place,  sufficient  pressure  is  put  on  the  ram  E  to 
bring  the  pattern  and  plate  A  into  contact  with  the 
lower  face  of  the  box  C.  The  latter  is  now  filled  with 
sand  and  the  frame  B  laid  upon  it,  the  latter  also  being 
filled  with  sand.  The  water  is  turned  on  again,  pressing 
the  lower  half-pattern  into  the  box  C,  and  the  upper  half 


318  PRACTICAL  IRON  FOUNDING 

into  the  frame  B,  after  which  the  ram  is  lowered,  leaving 
the  mould  complete  with  its  ingate.  It  will  be  observed 
that  the  top  half  of  the  pattern  is  carried  on  a  travelling 
wagon,  which  can  be  run  aside  when  the  sand  is  being 
shovelled  into  the  boxes.  A  series  of  superimposed 
mould  is  shown  in  Fig.  216. 

The  larger  the  number  of  moulding  machines  of  a 
single  type  and  size  used  in  a  foundry,  the  better  chance 
is  there  to  make  economical  arrangements  in  the  depart- 
ment. In  some  English  shops,  a  circus  is  used  for  load- 
ing and  conveying  away  the  boxes. 
It  is  an  annular  table  suspended  by 
rods  from  a  central  pillar,  around 
which  it  is  turned.  In  other  cases 
a  conveying  table  runs  on  rollers. 
In  others,  parallel  rails  are  used, 
down  which  the  boxes  are  slid  away 
from  the  machines,  and  from  which 
they  are  taken  and  laid  to  right 


FIG.  216.—  MULTIPLE   anc*  ^  on  ^e  fl°or-    These  are  ad- 
MOULDS.  juncts  of  the  fixed  machines.    The 

use  of  portable  machines  is  growing 
in  the  case  of  light  machines.  If  a  large  number  of 
power  machines  can  be  utilised,  then  the  most  elabor- 
ately designed  plant  results  in  the  highest  economies, 
and  probably  a  hydraulic  plant  is  the  best  on  the 
whole  to  adopt.  When  many  machines  are  fixed  in  a 
large  system,  the  question  of  handling  the  sand  and 
moulds  offers  far  less  difficulty  than  in  the  case  of  a 
few  machines  only.  Not  only  does  it  pay  to  make  me- 
chanical provision  for  taking  away  the  finished  moulds, 
but  adequate  arrangements  can  be  made  for  conveying 
the  sand  and  empty  boxes  to  the  machines.  In  a  perfect 


EXAMPLES  OF  MOULDING  MACHINES      319 

system  such  as  this,  the  men  never  leave  the  machines, 
but  the  making  of  a  mould  is  the  work  of  several,  begin- 
ning with  the  sand  room,  and  ending  at  the  metal  pourer. 
Each  machine  operator  receives  his  sand  ready  mixed, 
and  boxes,  rams  the  whole,  or  probably  only  half  a  mould, 
which  is  conveyed  away  to  be  cored  by  others,  closed  by 
others,  and  poured  by  another  set  of  men. 

And  further,  in  this  entirely  mechanical  system,  which 
is  carried  on  with  nearly  military  precision,  other 
machines  besides  those  used  directly  in  moulding  attain 
an  importance  beyond  that  which  they  possess  in  the 
general  jobbing  shop  where  a  heterogeneous  class  of 
work  is  done.  Coremaking  machines  are  moulding 
machines  of  a  special  class,  and  the  use  of  these  is  ex- 
tending. The  fettling  department  is  affected,  for  machine- 
moulded  castings  are,  or  should  be,  cleaner,  more  free 
from  lumps  and  fins  than  hand-made  ones,  and  the 
tumbling  barrel  and  emery  wheels  are  able  to  deal  with 
these  in  quantity. 

Core  Making. — The  making  of  cores  by  machines  in- 
evitably follows  the  preparation  of  the  moulds,  or  other- 
wise the  coremakers  could  not  keep  pace  with  the  output 
of  the  machines.  For  many  years  cores  of  circular  and 
polygonal  sections  have  been  made  by  machines  provided 
with  pistons  which  push  the  cores  out  of  the  boxes  end- 
wise, but  these  now  constitute  only  a  small  section  of  the 
work  done  in  coremaking  machines.  The  largest  of 
these,  of  which  Fig.  217,  Plate  XV,  is  a  typical  ex- 
ample, resemble  the  hydraulic  moulding  machines,  the 
difference  consisting  chiefly  in  the  substitution  of  core- 
plates  for  the  pattern-plates.  In  these  cases  the  edges  of 
the  core-plates,  or  core-boxes  strictly,  are  chamfered  to 
cut  away  the  sand  and  prevent  it  getting  in  the  joints. 


320  PRACTICAL  IRON  FOUNDING 

This  is  shown  very  well  in  Figs.  218,  219,  Plate  XV,  in 
which  the  plates  are  seen  above  and  the  cores  moulded 
from  them  below.  The  output  of  Fig.  218,  in  which  the 
core-plates  measure  16  in.  by  12  in.,  is  48  cores  per  hour 
when  made  on  a  hand  machine.  The  output  of  Fig.  219 
with  core-plates  of  the  same  size  and  using  a  hydraulic 
machine  is  72  cores  per  hour  with  one  man.  Fig.  220  is 
an  example  of  a  coremaking  machine  of  another  kind,  in 
which  the  halves  are  withdrawn  laterally  by  means  of  a 
right-  and  left-hand  screw. 

Withdraival  of  Patterns. — Not  the  least  interesting  sec- 
tion of  machine  moulding,  from  the  operative  moulder's 
point  of  view,  are  the  mechanical  details  of  pattern 
moulding.  In  ordinary  work  we  may  say  broadly  that 
the  pattern  is  either  lifted  from  the  mould,  or  the 
mould  is  lifted  off  those  portions  of  the  pattern  which 
come  in  the  top;  and  the  pattern  is  self-contained — that 
is,  it  is  not  attached  to  or  cast  with  any  kind  of  plate. 
In  machine  moulding  both  lifts  are  common,  either 
the  pattern  or  the  mould  being  lifted.  But  besides  these, 
the  pattern  is  just  as  often  drawn  downwards,  leaving 
the  mould  above  it ;  or  the  mould  is  drawn  down- 
wards, leaving  the  pattern  above.  Neither  of  these  two 
last  would  be  practicable  in  hand  moulding,  as  they  are 
in  a  machine  where  vertical  movements  are  rigidly  con- 
trolled ;  and  their  practicability  widens  the  range  of  use- 
fulness of  the  moulding  machine.  Either  device  has 
advantages  over  the  other  in  certain  classes  of  work. 
In  the  case  of  shallow  patterns  it  makes  no  difference 
whether  the  box  or  pattern  is  lifted  off  the  pattern,  or 
the  pattern  drawn  down  from  the  box.  In  deep  work  it 
is  better  to  lift  the  pattern  and  plate  off  the  mould,  or  to 
lower  the  box  away  from  the  pattern.  In  either  of  the 


EXAMPLES  OF  MOULDING  MACHINES      321 

latter  plans  stripping  plates  must  often  be  used  to  pre- 
vent the  sand  from  breaking  down. 

Machine  moulding  has  developed  into  a  highly-organ- 
ized system  where  machines  and  methods  are  correlated 
and  interdependent.  It  has  effected  a  revolution  in  some 
shops  in  costs,  in  labour,  in  many  of  the  details  of  pattern 
work,  and  what  it  has  accomplished  in  the  few  will  be 


FIG.  220. — CORE-MAKING  MACHINE,  WITH  SAND  BIN. 

done  in  many  ere  long.  It  must  be  so  as  competition  be- 
comes more  severe.  Already  work  is  done  by  machines 
that  would  have  been  deemed  impossible  half-a-score  of 
years  since,  and  it  would  be  unwise  in  the  light  of  that 
advance  and  the  promise  of  the  future  to  attempt  to  set 
any  limits  to  the  capabilities  of  moulding  machines,  and 
the  systems  of  which  they  form  a  part. 

Boxes. — It  may  be  taken  as  a  fact  that  many  moulding 
boxes  in  the  near  future  will  be  designed  specially  for  one 

Y 


322  PRACTICAL  IRON  FOUNDING 

class  of  work  only.  To  some  extent  this  holds  good  now, 
just  as  it  does  in  the  case  of  large  numbers  of  machine 
tools  which  are  only  seen  in  the  shops  in  which  they  have 
been  designed,  if  not  built.  Pulley  moulding  machines 
are  a  familiar  example  of  special  machines;  so  are  car  or 
railway-wagon  wheel  moulding  machines,  and  machines 
for  moulding  firebars,  others  for  radiator  pipes,  and  for  the 
vertical  parts  of  radiators.  In  these,  stripping  plates  are 
used,  and  power  pressing,  notwithstanding  that  the  bars 
and  ribs  are  deep,  and  the  spaces  both  between  bars  and 
ribs  are  very  narrow.  The  numbers  required  off  pay  for 
the  cost  of  fitting  up  stripper  plates  and  presser  heads, 
and  though  the  work  is  massive,  the  application  of 
hydraulic  power  robs  it  of  all  excessive  labour.  Pipes 
are  moulded  by  these  up  to  6  ft.  in  length,  and  firebars 
up  to  60  in.,  and  several  firebars  are  moulded  at  once. 

Mechanical  Pressing. — It  has  been  made  clear  that  me- 
chanical pressing  cannot  in  all  cases  properly  supersede 
the  necessity  for  hand  ramming.  It  is  claimed  for  presser 
heads  that  the  moulds  are  all  pressed  uniformly,  and 
that  therefore  castings  will  all  come  out  alike.  But  uni- 
form pressing  is  just  what  is  not  desirable  in  many 
moulds,  because  uniformity  of  pressure  over  the  area  of 
the  head  does  not  mean  the  same  thing  at  different 
depths  of  irregular  moulds.  Besides  which,  it  is  well 
known  that  some  portions  of  many  moulds  must  be 
rammed  harder  than  others.  In  proof  of  these  facts, 
which  are  obvious  to  moulders,  many  of  the  most  suc- 
cessful machines  in  use  now  are  made  for  hand  ram- 
ming. Power  ramming  has  its  place  in  foundries,  but 
its  utilities  are  limited  to  certain  classes  of  work,  or  to 
work  for  which  suitable  dummy  presses  are  cut.  Many 
devices  have  been  patented  to  facilitate  the  ramming  by 


EXAMPLES  OF  MOULDING  MACHINES      323 

power  of  deep  patterns  and  irregularly  shaped  contours. 
They  emphasise  the  fact  that  power  ramming,  except  in 
plain,  rather  flat  work,  is  not  successful,  apart  from  the 
assistance  derived  from  suitable  devices. 

Jar-Ramming  Machines. — The  chief  utilities  of  these 
machines  (the  latest  type)  lie  in  the  ramming  of  deep 
moulds.  They  are  not  suitable  for  shallow  ones  unless 
an  excess  of  sand  is  used.  Depth  is  necessary  to  ensure 
consolidation  of  the  sand,  which  is  increased  by  the  jar- 
ring from  twenty-five  to  thirty  per  cent.  The  sand  is 
denser  at  the  bottom  than  at  the  top.  The  upper  stratum  is 
usually  lightly  rammed  by  hand  after  the  jarring.  A  sand 
frame  has  to  be  used  to  confine  the  extra  sand  required 
for  consolidation.  No  venting  is  required.  The  economies 
are  enormous.  The  actual  jarring  does  not  occupy  more 
than  half  a  minute.  A  flask  can  be  placed  on  the 
machine,  jar-rammed,  and  removed  in  two  minutes.  A 
similar  mould  of  moderate  size  if  hand  rammed  would 
occupy  from  twenty  minutes  to  half  an  hour.  There  is  a 
vast  future  for  these  machines  though  they  are  little 
known  at  present. 

Figs.  221  and  222,  Plate  XVI,  illustrate  the  Hermann 
jar-ramming  machine  constructed  by  the  Pneumatic  En- 
gineering Appliances  Company,  Limited,  of  Westminster, 
S.W.  This  is  built  both  for  stripping-plate  work  and  for 
turn-over  moulding,  the  latter  being  an  arrangement 
which  is  removable,  and  not  shown  in  the  photograph. 
The  parts  of  the  jarring  mechanism  are  enclosed  in  the 
cylinder  seen  at  the  base  of  the  machine,  to  which  air  is 
admitted  through  a  valve  to  effect  the  jarring.  The 
mould  is  raised  off  the  pattern  by  the  pneumatic  cylinders 
at  the  end,  and  the  separation  of  pattern  and  mould  can 
be  effected  either  upwards  or  downwards  as  desired.  A 


324  PRACTICAL  IRON  FOUNDING 

special  feature  of  the  machine  is  the  oil-governing  ar- 
rangement in  which  the  cylinders  for  raising  and  lower- 
ing the  pattern  table  and  moulding  box  are  governed 
perfectly,  so  preventing  injurious  shock.  The  oil  tank  is 
seen  at  the  front  in  Fig.  222.  The  machine  is  set  to 
strike  about  120  blows  a  minute,  and  twenty-five  to  fifty 
jars  are  sufficient  to  set  the  sand  in  an  ordinary  mould. 

The  action  of  the  jarring  machine  may  be  understood 
by  regarding  it  as  composed  of  two  essential  elements, 
the  jarring  table  which  carries  the  pattern  and  mould, 
and  the  anvil.  The  table  is  lifted  and  dropped  repeatedly 
and  rapidly  on  the  anvil.  But  in  order  to  lessen  the  re- 
sulting shock  the  latter  is  cushioned,  and  is  often  also 
made  to  lift  to  meet  the  falling  table.  In  the  delicate 
relative  adjustments  of  these  two  movements  the  effi- 
ciency of  the  machine  lies.  Hence,  though  the  action  of 
the  jarring  machine  is  simple,  the  details  have  to  be 
worked  out  with  care,  because  the  jar  or  shock  which  is 
the  efficient  agent  in  the  consolidation  of  the  sand  is 
also,  if  too  severe,  destructive  to  the  machine,  the  flasks, 
the  sand  of  the  mould,  and  even  to  structures  in  the 
immediate  vicinity. 

The  weight  of  the  table,  the  flask,  pattern,  and  sand, 
is  lifted  to  a  height  which  varies  from  say  2  in.  to  3  in.  on 
an  average,  and  is  then  dropped  on  the  anvil,  the  action 
being  repeated  perhaps  thirty  or  forty  times  within  the 
space  of  half  a  minute.  The  early  blows  are  more  effi- 
cient than  the  later,  and  longer  drops  also  are  more  so 
than  shallow  ones.  But  the  deeper  the  drop  and  the 
more  prolonged  the  action,  the  more  severe  are  the 
effects  on  the  mechanism  of  the  mould.  Destructive 
effects  can  only  be  avoided  by  a  very  solid  construction, 
and  by  the  recognition  of  certain  facts  which  are  con- 


EXAMPLES  OF  MOULDING  MACHINES      325 

cerned  with  the  impact  of  falling  bodies.  Fracture  of  the 
sand  will  also  occur  in  any  case  if  there  is  imperfect  fit- 
ting of  patterns,  flasks,  or  mechanism,  which  would  cause 
slight  relative  movements  to  take  place. 

By  the  laws  of  impact  the  heavier  the  anvil  the  better, 
so  that  an  anvil  bedded  on  rock  would  be  the  ideal  one. 
But  a  rock  bottom  would  be  bad  from  another  point  of 
view.  It  would  transmit  the  ground  waves  set  up  by  the 
machine  to  a  long  distance,  with  disagreeable  if  not 
destructive  effects  to  neighbouring  walls,  floors,  and 
buildings.  And  a  very  heavy  cast  iron  anvil  would  in- 
crease the  cost  of  the  machine  unduly.  The  practice 
therefore  is  to  make  the  anvil  of  about  the  same  weight 
as  the  jarring  table  when  loaded  with  its  pattern,  flask, 
and  sand,  and  to  bed  it  on  a  timber  cribbing.  An  anvil 
cushioned  in  this  way  will,  when  struck  by  a  table  of  its 
own  weight  suddenly  acquire  one  half  the  velocity  of  the 
table  at  the  instant  of  impact,  after  which  both  table  and 
anvil  will  be  brought  to  rest  by  the  yielding  resistance  of 
the  timber  foundation.  The  loaded  table  thus  loses  only 
one  half  the  velocity  it  would  lose  by  falling  on  an  anvil 
of  infinite  weight,  as  a  rock  foundation,  and  the  ramming 
effect  is  one  quarter  as  much,  being  measured  by  the 
square  of  the  change  in  velocity. 

Compressed  air  is  used  for  the  operation  of  these 
machines,  its  supply  being  controlled  by  a  valve  which 
is  put  into  and  out  of  action  by  a  lever,  but  the  action 
of  which  is  continuous  and  automatic  as  long  as  the 
lever  is  retained  in  a  certain  position.  There  are  two 
general  methods  of  operation  in  use.  In  one  the  air 
which  lifts  the  jarring  table  is  exhausted  into  the  atmo- 
sphere during  the  falling  stroke.  In  the  other  it  passes 
into  the  anvil  cylinder  and  assists  in  raising  the  latter  to 


326  PRACTICAL  IRON  FOUNDING 

meet  the  falling  table,  the  rest  of  the  work  being  affected 
by  compressed  springs  under  the  anvil.  When  the  air  is 
not  exhausted  thus,  the  springs  do  all  the  work  of  lifting. 
The  idea  is  to  cause  the  momentum  of  the  rising  anvil 
to  be  approximately  equal  to  that  of  the  falling  table  at 
the  instant  of  impact,  and  so  produce  a  maximum  of 
jarring  effect  on  the  sand  without  injurious  shock  on  the 
foundations,  on  the  sand,  or  the  mould  fittings.  By  this 
action  the  tendency  of  the  table  to  spring  away  from  the 
anvil  after  impact  is  met  and  neutralized,  since  the 
rising  anvil  remains  in  contact  with  it,  and  one  of  the 
causes  which  would  tend  to  produce  damaged  moulds  is 
eliminated. 

Specialization  in  the  foundry. — We  are  coming  into  a 
time  in  which  the  work  of  the  foundry  is  likely  to  un- 
dergo radical  changes,  not  only  with  respect  to  the  em- 
ployment of  moulding  machines,  but  of  the  system  of 
which  they  form  an  important  section — though  but  a 
section  after  all.  For,  though  the  installation  of  a 
machine  or  machines  in  a  shop  is,  in  the  first  place, 
usually  done  with  the  idea  of  helping  the  jobbing  work, 
or  that  which  is  but  slightly  repetitive,  dissatisfaction 
with  all  the  methods  in  vogue  usually  results,  as  the 
latent  possibilities  of  the  innovation  in  moulding  be- 
comes apparent. 

The  introduction  of  any  moulding  machines,  therefore, 
however  simple  in  design,  and  few  in  numbers  only,  is 
often  the  beginning  of  a  wider  system,  of  which  this 
particular  machine  forms  but  a  single  detail.  Though 
the  advantages  which  it  confers  over  the  unassisted  work 
of  the  floor  or  bench  are  great,  its  ultimate  tendency  is 
to  lead  to  economies  in  all  the  work  that  leads  up  to 
the  machine,  and  in  that  which  follows.  The  desire  to 


EXAMPLES  OF  MOULDING  MACHINES      327 

specialize  grows  as  the  economies  of  one  particular 
section  of  specialization  becomes  apparent.  It  tends  to 
introduce,  and  must  with  some  machines  introduce, 
new  types  of  moulding  boxes,  new  methods  of  mixing 
and  conveying  sand,  of  grading  iron,  of  making  cores. 
The  labour  problem  has  to  be  wholly  readjusted,  while 
questions  come  up  for  solution  that  never  troubled  old- 
time  moulders — such  as  the  installation  of  power  (steam, 
hydraulic,  or  pneumatic)  in  the  foundry. 

Perhaps  the  keynote  in  the  problems  which  are  raised 
is  to  be  sought  in  the  word  "  specialization."  Firms  who 
are  able  to  specialize  sufficiently,  can  choose  almost  any 
system  and  moulding  plant,  and  make  a  success  of  it. 
Those  who  have  grown  accustomed  to  one  system  are 
naturally  prejudiced  in  its  favour,  and  it  is  hard  for  out- 
siders to  say  whether  it  is  worse  or  better  than  any  other 
for  particular  shops.  Generally,  one  would  like  to  believe 
that  firms  can  be  trusted  to  know  their  own  business  re- 
quirements better  than  any  others  can  know  them.  Yet 
this  is  not  always  true,  because  outsiders  in  walking 
through  shops  see,  almost  as  if  by  intuition,  things  which 
might  be  improved;  though  long  habit  in  the  case  of 
those  who  have  grown  with  the  system  has  developed 
a  kind  of  permanent  set,  or,  to  use  another  simile,  a 
colour  blindness,  which  is  prejudicial  to  clear  insight 
and  reform* 

An  instance  of  what  we  mean  by  extreme  specializa- 
tion is  this: 

In  the  machine-made  moulds  in  the  ordinary  work  of 
the  foundry,  the  box  parts  are  put  together  either  by 
hand  or  by  the  crane,  in  both  cases  the  controlling  power 
being  exercised  by  the  hands  of  the  men.  There  is  not 
very  much  involved  in  this,  it  is  true,  but  it  does  some- 


328  PRACTICAL  IRON  FOUNDING 

times  happen  that  a  cope  will  be  damaged  by  not  being 
lowered  quite  horizontally,  or  hitching  of  the  pins  in  the 
holes  occurs,  or  because  the  movement  is  jerky.  And 
when  intricate  cores  are  being  inserted,  these  may  be- 
come pushed  aside,  or  crushed  in  the  act  of  closing  the 
mould.  Now  a  machine  is  made  by  which  the  top  is 
lowered  on  the  bottom  box,  perfectly  plumb,  and  it 
thus  fulfils  the  same  function  in  the  accurate  closing 
of  the  mould  that  the  moulding  machine  does  in  a 
square  lift  of  the  pattern.  It  stands  on  a  circular  base, 
carrying  the  table  on  which  the  bottom  box  is  laid.  Two 
uprights  stand  up  from  the  table,  and  carry  centring  pins 
that  pass  from  bottom  to  top.  The  top  box  being  sup- 
ported by  hydraulic  pressure,  the  removal  of  the  latter 
allows  the  box  to  descend,  along  with  a  supporting  cross- 
piece  moving  in  guides  underneath  the  table.  Or,  worm 
gear  is  substituted  for  hydraulic  power.  The  capacity 
of  these  machines  ranges  from  boxes  of  24,  36,  and 
48  in.  in  length.  These  are  limited  by  the  distances  be- 
tween the  uprights,  but  there  is  no  limit  to  any  width, 
within  reason. 


CHAPTEE  XV 

MACHINE  MOULDED  GEARS 

GEAR  wheel  moulding  machines,  though  extensively  used, 
are  not  found  in  all  shops,  so  that  there  are  still  many 
moulders  and  pattern  makers  who  have  had  no  experi- 
ence whatever  of  them.  There  are  six  or  seven  different 
types.  The  machine  of  Messrs.  Buckley  and  Taylor,  of 
Oldham,  is  selected  for  illustration  in  this  volume.  Before 
discussing  the  actual  moulding  of  wheels,  the  construc- 
tion of  the  main  framework  of  the  machine  may  be 
described. 

The  illustrations,  Figs.  223  and  224,  represent  a  table 
machine,  that  is,  one  in  which  the  moulding  flasks  are 
set  and  rammed  on  a  table.  In  the  floor  machines  the  lower 
portion  of  the  work  is  rammed  in  the  foundry  floor,  and 
a  top  box  is  employed  to  form  the  cope  mould  only. 
The  first  machines  are  used  for  wheels  of  small  and 
of  moderate  dimensions,  the  second  for  those  of  large 
diameter.  The  table  machines  are  entirely  self-contained, 
but  all  the  upper  portions  of  the  floor  machines  are 
portable,  that  is,  the  essential  dividing  apparatus  and 
carrier  arms  are,  when  required  for  use,  set  down  over  a 
central  pillar  or  base  sunk  permanently  and  levelled  in 
the  foundry  floor.  The  machine  of  Messrs.  Buckley  and 
Taylor  is  made  capable  of  employment  in  each  capacity, 
the  upper  portion  being  removable,  and  the  base,  with 
the  dividing  apparatus,  being  adapted  to  fit  into  a 

329 


330 


PRACTICAL  IRON  FOUNDING 


massive  bed  in  the  floor,  while  a  radial  arm,  made  to 
slide  in  vee'd  guides  screwed  upon  the  bed,  is  substituted 


FIG.  223. — WHEEL  MOULDING  MACHINE. 

for  the  arched  arm.  This  radial  arm  carries  at  one  end 
the  vertical  slides  for  the  tooth  block,  and  the  radius  of 
the  wheel  to  be  moulded  is  only  limited  by  the  length 


MACHINE  MOULDED  GEARS 


831 


of  the  arm.    Wheels  up  to  25  ft.  are  moulded  in  the  floor 
machine. 

Figs.  223,  224,  are  an  elevation  and  plan  respectively  of 


x£v''-''  -^  •£''•'.    > 

,-?%'  -^Ei^-^^v v xN-&  \      " 

'l/jS/^^C*''.-t^'r'\''-'  •      '    I  .'    '  !        '    \     *     v 

fft-iiiSKS-.    •-'•-•....    .-    -•'•/    ,  'i    \       » 


FIG.  224. — WHEEL  MOULDING  MACHINE.. 

the  machine.    In  these,  H  is  a  strong  foundation 
against  which  the  bed  I  is  bolted.    The  table  fits     U 
by  means  of  a  turned  pin  into  the  boss  of  the  foundation 
plate  IT.    This  table  carries  the  moulding  flask  T,  on 
which  is  shown  a  sectional  portion  of  a  spur  wheel  mould, 
and  is  revolved  by  means  of  the  dividing  wheel  F,  and 


332  PRACTICAL  IRON  FOUNDING 

tangent  screw  E.  The  bed  /  carries  the  arched  arm  J, 
at  the  extremity  of  which  moves  the  vertical  slide  7i,  to 
which  the  tooth  block  is  bolted. 

The  essential  mechanism  by  which  the  dividing  out  of 
the  wheel  teeth  is  effected  is  as  follows.  The  dividing 
wheel  F  is  attached  to  the  under  side  of  the  table.  Into 
this  gears  the  tangent  screw  E.  This  is  actuated  by  the 
handle  A  turning  around  on  a  notched  division  plate  V. 
The  short  hollow  pillar  beneath  encloses  a  pair  of  small 
mitre  wheels,  through  which  the  motion  of  the  handle  A 
is  communicated  to  the  shaft  7>,  at  the  opposite  end  of 
which  the  first  change  wheel  C  is  placed.  This  gears 
through  the  idle  wheel  G  with  the  change  wheel  C'  upon 
the  tangent  screw  shaft  D.  Any  gears  of  the  set  usually 
supplied  with  these  machines  are  interchangeable  at 
C,  C'  and  G,  a  slotted  quadrant  plate,  together  with  the 
idle  gear  G  furnishing  the  means  of  adjustment  for 
centres.  Of  course  the  idle  wheel  counts  for  nothing  in 
the  calculation  of  the  train. 

Suppose  the  tooth  block  to  have  been  set  at  the  correct 
radius  for  any  given  wheel  to  be  moulded,  by  the  sliding 
along  and  clamping  of  the  arm  J,  on  the  bed  /.  It  is 
evident  that  a  single  turn  of  the  single  threaded  worm  E 
will  pass  the  dividing  wheel  F  a  distance  equal  to  one 
tooth.  Hence,  having  wheels  of  equal  diameter  at  C  and 
C',  and  giving  one  turn  to  the  handle  A,  a  wheel  would 
be  moulded  on  the  table  having  precisely  the  same 
number  of  teeth  as  the  dividing  wheel.  But  by  employ- 
ing unequal  change  gears  to  connect  the  handle  shaft  B, 
and  the  worm  shaft  D,  and  by  doubling  or  trebling  or 
quadrupling  the  number  of  turns  of  the  handle,  or  by 
giving  to  the  handle  some  definite  fractional  portion  of  a 
turn  only,  we  have,  as  in  the  screw-cutting  lathe,  a  means 


MACHINE  MOULDED  GEARS  333 

for  establishing  almost  any  number  of  proportional  rela- 
tionships between  the  number  of  teeth  in  the  dividing 
wheel  F  and  the  wheel  to  be  moulded.  Hence  the  rule, 
"  As  the  number  of  teeth  in  the  dividing  wheel  is  to  the 
number  of  teeth  in  the  wheel  required  to  be  moulded,  so 
is  the  number  of  teeth  in  the  wheel  on  the  handle  shaft 
to  the  number  of  teeth  in  the  wheel  required  on  the  worm 
shaft." 

Thus:  suppose  a  wheel  of  100  teeth  has  to  be  moulded. 
The  dividing  wheel  F  has  usually  180  teeth.  Put,  say,  a 
90  toothed  wheel  on  the  handle  shaft.  Then:— 180: 
100  :  90  : :  50.  A  wheel  of  50  teeth  would  therefore  be 
placed  on  the  worm  shaft  7J,  and  one  turn  given  to  the 
handle  shaft  B.  But  supposing  we  have  not  got  a  wheel 
of  50  teeth,  we  can  multiply  50  by  2  =  100,  and  put  a  wheel 
of  100  teeth  on  the  worm  shaft.  But  then  we  must  give 
two  turns  to  the  handle.  For  in  any  case,  if  we  multiply 
the  quotient  which  gives  the  number  of  teeth  on  a 
change  wheel  on  the  worm  shaft,  we  must  also  multiply 
the  number  of  turns  of  handle,  or  if  we  halve  the  number 
of  teeth,  we  must  halve  the  number  of  turns  given  to  the 
handle. 

If  we  are  doubtful  of  the  wheels,  they  may  be  proved 
thus.  Divide  the  number  of  teeth  in  the  wheel  on  the 
handle  shaft  by  the  number  of  teeth  in  the  wheel  on  the 
worm  shaft,  multiply  the  quotient  by  the  number  of 
turns  given  to  the  handle.  The  product  will  be  equal  to 
the  quotient  of  the  number  of  teeth  in  the  dividing  wheel 
divided  by  the  number  of  teeth  in  the  wheel  to  be 
moulded.  Thus  in  our  lirst  example: — 


334  PRACTICAL  IRON  FOUNDING 

Handle  shaft     ...     90 

-1-8x1  turn  =  1-8 


Worm  shaft ....     50 
Dividing  wheel  .     .     .  180 


=  1-8 


Wheel  to  he  moulded    100 

The  mechanism  for  actuating  the  tooth  block  is  as  fol- 
lows:— The  radius  of  the  block  is  adjusted  by  means  of 
the  arched  arm  J,  which  travels  upon  the  bed  7,  to  or 
from  the  centre  of  the  table.  This  is  adjusted  with  the 
screw  L,  and  clamped  by  the  pinching  screws  in  its  foot 
in  its  required  position,  remaining  immovable  during  the 
whole  period  of  the  ramming  of  the  wheel  teeth.  The 
vertical  slide  K  is  carried  in  vee'd  guides,  which  have 
provision  for  taking  up  wear.  It  is  actuated  by  the 
small  hand  wheel  0  turning  the  worm  P,  which  re- 
volves the  worm  wheel  (t>,  upon  the  spindle  of  which  is 
the  spur  pinion  R,  gearing  with  the  rack  S  attached  to 
the  vertical  slide  K.  The  slide  is  counterbalanced  by  the 
weight  M.  The  vertical  movement  of  the  slide  is  checked 
at  the  proper  position  by  means  of  the  adjustable  stop  U, 
so  that  there  is  no  risk  of  the  tooth  block  being  thrust 
down  too  hard  upon  the  sand  bed.  The  lower  portion  of 
the  slide  receives  the  carrier  N  to  which  the  tooth  block 
is  attached. 

The  essential  portions  of  the  machine  are  therefore 
the  firm  base  H,  the  revolving  table  carrying  the  flask, 
T,  with  the  dividing  apparatus,  the  arm  J  moving  radially 
in  reference  to  the  table,  and  the  provisions  for  the 
vertical  movement  of  the  tooth  block.  The  tables  IT,  A", 
are  simply  convenient  attachments  for  the  reception  of  the 
moulder's  small  tools.  We  are  now  in  a  position  to  take 
up  the  details  of  the  actual  moulding  of  toothed  wheels. 


MACHINE  MOULDED  GEARS 


335 


years. — These  are  moulded  very  simply.  The 
teeth  are  formed  with  a  block,  and  the  arms  by  means  of 
cores.  The  block,  Fig.  225,  in  this  case,  has  two  teeth 
only,  and  the  inter-tooth  space  alone 
is  used  in  the  formation  of  the  mould. 
Three  teeth,  Fig.  226,  or  four  are  often 
used  on  the  block.  A  bed  is  first  struck, 
Fig.  227,  with  a  board  attached  to  the 
striking  bar  A,  the  depth  13  being  equal 
to  the  depth  of  the  face  of  the  wheel,  FIG.  225. — TOOTH 
the  bottom  edge  C  striking  the  bed,  BLOCK. 

the  top  edge  D  the  top  or  joint  face. 
The  striking  bar  A  in  Fig.  227  is  turned  to  fit  into  the 
bored  hole  in  the  centre  boss  of  the  table  in  Figs.  223, 


FIG.  226.— TOOTH  BLOCK. 


FIG.  227. — STRIKING  BOARD. 


224.  The  strap  E  is  bored  to  fit  over  this  bar,  and 
its  shoulder  F  is  cut  to  a  definite  distance  from  the 
centre  of  the  bar,  so  that  the  radius  of  any  striking  board 
is  less  than  the  radius  of  the  wheel  by  the  distance  G. 


336  PRACTICAL  IRON  FOUNDING 

The  central  bar  or  post  A  is  removable  at  pleasure.  Its 
purpose  is,  first,  the  carrying  of  the  strap  or  bracket  E, 
and  second,  it  is  the  part  from  which  the  radius  of  the 
tooth  block  is  measured. 

The  vents  from  the  bed  are  carried  down  to  a  coke 
bed  if  the  wheel  is  moulded  in  the  floor,  to  the  bottom  of 
a  flask,  if  in  a  flask.  The  tooth  block  is  screwed  to  the 
carrier,  set  to  the  correct  radius,  either  by  means  of  a 
strip  or  gauge  cut  to  reach  the  precise  distance  from  the 
post  of  the  machine  to  some  portion  of  the  block,— 
either  root  or  point,  and  the  machine  is  clamped  to  pre- 
serve that  distance  constant.  The  length  of  the  gauge 
will  be  equal  to  the  radius  of  the  root  or  point,  as  the 


FIG.  228. — RADIUS  GAUGE. 

case  may  be,  minus  the  radius  of  the  post.  Or  a  gauge, 
Fig.  228,  may  be  cut  to  fit  partly  round  the  post  A  in 
Fig.  227,  and  the  radius  be  marked  upon  that  to  root  or 
point.  The  radius  once  obtained,  and  the  arm  clamped, 
the  gauge  strip  is  no  longer  required.  The  block  is 
lowered  until  its  lower  face  bears  upon  the  sand  bed,  and 
then  the  stop  U,  Fig.  224,  is  clamped,  and  all  is  in  readi- 
ness for  the  ramming  of  the  teeth. 

It  will  be  noticed  that  the  end  II  of  the  board  in 
Fig.  227  is  bevelled.  This  is  not  always  done,  but  it  is 
a  good  plan,  as  is  apparent  by  the  sectional  view  in 
Fig.  229,  where  the  tooth  block  is  seen  in  its  exact 
relationship  to  the  circular  wall  of  sand  A,  within  which 
it  is  rammed  up.  Space  is  left  between  the  points  of  the 
teeth,  and  the  outer  roughly-struck  wall  of  sand,  in  order 


MACHINE  MOULDED  GEARS  337 

to  give  a  narrow  zone  for  ramming  facing  and  strong- 
sands  into,  and  the  wall  is  made  sloping,  because  it  is 
easier  to  sweep  up  than  a  perpendicular  wall,  from  which 
the  sand  would  tumble  down. 

Facing  sand  is  thrown  into  the  space  between  the  wall 
A  and  the  teeth,  and  strengthened  with  nails  (dotted). 
The  sand  is  rammed  between  the  teeth  with  a  small 
pegging  rammer,  being,  for  these  small  teeth,  only 
a  rod  of  round  iron  flattened  and  narrowed  at  one  end. 
When  the  inter-tooth  space  is  filled,  the  sand  is  levelled 
over  with  a  flat  rammer,  scraped  and  sleeked  with  the 
trowel,  and  vented  diagonally,  the 
vents  7}  passing  into  a  main  vent 
(7,  either  going  down  to  a  coke 
bed,  or  coming  out  in  the  joint  of 
the  flask.  Only  the  inter-tooth 
space  gives  the  tooth  shape,  and 
one  tooth  space  or  more  may  be 

rammed  at  a  time  (see  Figs.  225,    ^IG  229. RAMMING 

226).  The  hinder  part  and  the  OF  TOOTH  BLOCK. 
ends  of  the  block  are  slightly 
rapped  with  the  hammer  previous  to  the  withdrawal  of 
the  teeth ;  but  there  is  no  rapping  in  the  sense  in  which 
it  is  employed  with  ordinary  patterns.  The  pattern  is 
simply  started,  and  the  block  lifted  without  any  sensible 
lateral  play.  There  is,  or  should  be,  no  taper  in  the  tooth 
space,  and  the  sand  would  therefore  become  torn  up  on  the 
withdrawal  of  the  block  but  for  the  fact  that  it  is  held 
down  by  a  stripper  bit  cut  to  the  shape  of  the  inter-tooth 
space,  upon  which  the  moulder  presses  the  two  forefingers 
of  his  left  hand,  while  elevating  the  slide  with  his  right. 
Having  lifted  the  block  clear  of  the  mould,  the  re- 
quisite number  of  turns  is  given  to  the  handle  shaft,  and 


338 


PRACTICAL  IRON  FOUNDING 


the  block  thereby  carried  round  a  distance  equal  to  the 
pitch.  The  slide  is  then  lowered,  bringing  the  block  into 
a  suitable  position  for  ramming  the  succeeding  tooth  or 
teeth,  the  process  for  each  tooth  being  simply  a  repetition 
of  the  first.  In  order  that  the  outside  faces  of  the  teeth 
on  being  lowered  shall  not  scrape  or  push  aside  the  sand 
already  rammed,  taper  is  given  to  those  faces,  as  shown 
in  Fig.  226,  so  that  the  outer  edges  of  the  block  do  not 
come  into  actual  contact  with  the  sand  at  all,  or  at  least, 
only  when  finally  in  place,  the  top  edge  may  just  coincide. 
Also,  to  prevent  the  sand  from  tumbling  down  on  the  side 


FIG.  230. 

SECTION  OP  WHEEL  MARKED 
ON  BOARD. 


FIG.  231. 

SECTION  THROUGH 
MOULD. 


opposite  to  that  which  is  already  rammed,  a  block  of 
wood  is  laid  against  the  tooth  block  to  sustain  the  sand 
in  that  direction  during  ramming. 

Striking  boards  also  are  desirable,  though  not  always 
necessary  in  the  case  of  perfectly  plain  wheels.  But  it  is 
better  to  use  them  even  for  these.  A  plain  wheel  can  be 
made  by  ramming  the  teeth  round  on  a  level  bed,  insert- 
ing the  arm  cores,  and  covering  with  a  plain  top.  But  if 
a  board  like  Fig.  227  is  used,  it  forms  a  wall  of  sand 
within  which  the  facing  sand  used  for  surrounding  the 
wheel  teeth  is  rammed,  and  it  gives  the  exact  depth  also 


MACHINE  MOULDED  GEARS 


339 


of  the  wheel,  and  the  face  upon  which  the  top  is  to  be 
laid.  Such  a  board  is  made  parallel,  so  that  a  spirit  level 
is  tried  upon  the  top  edge,  without  which  precaution  the 
board  may  become  tilted  a  little,  and  strike  a  bed  that  is 
slightly  dished.  The  edges  are  chamfered  like  those  of  a 
loam  board.  A  careful  man  will  mark  the  section  of 
wheel  rim  and  boss  upon  the  board,  Fig.  230,  and  cross 
hatch  it  as  a  guide  to  the  moulder.  Sometimes  a  narrow 
strip  is  tacked  on  the  board  at  the  exact  radius  of  the 
points  of  the  wheel  teeth,  instead  of  indicating  the  teeth 


FIG.  232.  FIG.  233. 

BOARDS  FOR  STRIKING  HALF  SHROUDINGS. 

with  crossing  lines,  as  in  Fig.  230.    Fig.  231  shows  the 
mould  in  section. 

Half  shroudings  furnish  the  commonest  cases  in  which 
the  use  of  a  plain  top  is  not  possible.  Made  in  the  man- 
ner first  mentioned,  by  ramming  the  top  on  a  reverse 
mould,  Fig.  232  shows  the  striking  board  used,  the  edge 
A  being  for  the  bottom  and  the  edge  B  for  the  top,  both 
edges  also  including  the  bosses,  the  position  of  the  board 
being  of  course  reversed  for  the  separate  operations. 
Usually  one  piece  of  board  serves  thus  for  both  the 
opposite  edges,  being  cut  to  the  shapes  required;  but 
sometimes  separate  boards  are  made.  The  edge  B  is 


340 


PRACTICAL  IRON  FOUNDING 


used  first,  striking  a  reverse  top  on  which  the  actual  top 
mould  is  rammed.  Afterwards  the  sand  is  dug  out  and 
the  edge  A  is  used,  striking  the  wheel  face  to  the  proper 
depth  below  the  top  face.  The  advantage  of  this  method 
is  that  the  top  and  bottom  are  bound  to  be  concentric, 
the  former  having  been  rammed  in  the  actual  place 
which  it  will  again  occupy  after  the  ramming  of  the  teeth 
and  the  coring  up  are  done.  In  the  other  method  the 
edge  which  strikes  the  top  is  like  that  one  which  strikes 
the  bottom,  and  the  fitting  of  the  boxes  ensures  the  top 


FIG.  234. — BOARD 
FOR  PLATED  WHEEL. 


FIG.  235.— WHEELS  CAST 
TOGETHER. 


and  bottom  being  concentric.  Or  a  check  is  used,  as  in 
loam  work. 

Fig.  233  shows  a  board  used  for  striking  a  top  mould 
directly,  the  shape  of  the  half-shrouded  wheel  being 
marked  upon  it.  The  correspondencies  are  clear.  The 
interior  is  formed  with  cores,  for  which  prints  are  pro- 
vided. Fig.  234  is  a  board  for  a  plated  wheel  in  which 
the  recessing  is  swept  in  the  mould.  Generally,  when  a 
wheel  is  plated,  the  plate  and  interior  of  the  rim  are 
formed  by  annular  cores  made  in  an  annular  box. 

When  wheels  have  to  be  cast  together,  as  in  Fig.  235, 
or  in  other  combinations,  they  can  be  bedded  in  the  floor, 
making  suitable  joints  for  shroudings,  and  moulding  the 
pinion  first.  Or  they  can  be  prepared  in  two  separate 
boxes,  which  will  have  to  be  centred  properly. 


MACHINE  MOULDED  GEARS 


341 


When  facings  are  cast  on  the  rim,  or  on  the  arms  of 
wheels  moulded  from  tooth  blocks,  they  are  set  in  place 
singly  by  measurement— work  that  can  be  done  by  centre 


FIG.  236. — LARGE  BORE  FORMED  WITH  SEGMENTAL  CORES. 

and  circular  lines  set  out  on  the  plain  bed.  The  pattern- 
maker is  usually  called  upon  to  do  this.  When  such 
pieces  come  in  the  top,  there  is  an  advantage  in  laying 


FIG.  237. — LARGE  BORE  AND  ARMS  FORMED  WITH 
SEGMENTAL  CORES. 

them  on  a  reverse  mould  and  ramming  the  top  over 
them. 

The  tooth  block  moulds  a  ring  of  teeth  only,  and  the 
interiors  of  the  wheels  have  to  be  formed  with  cores. 


342 


PRACTICAL  IRON  FOUNDING 


These  are  made  from  boxes,  and  are  covered  with  a  top, 
plain  or  otherwise,  with  boss  facings  bedded  in  top  and 
bottom.  Usually  the  H-  section  arm  is  employed  for 
wheels  made  by  machine,  because  it  is  easier  of  forma- 
tion in  cores  than  any  other  shape ;  but  any  shape  can 


FIG.  238. — ARM  CORE.       FIG.  239. — SECTION  OF  CORE. 

be  made  if  required.   In  patterns  the  J_  tyPe  of  arm  is 
easiest  to  make. 

Anns. — The  cores  for  arms  are  made  in  dried  sand, 
and  set  in  place  without  prints,  by  measurement  alone. 


FIG.  240.— GRID 
FOR  ARM  CORE. 


FIG.  241.  FIG.  242. 

ABUTTING  CORES.      DISHED  ARM. 


The  arms  of  spur  wheels  are  usually  H  shaped  in  sec- 
tion, partly  because  of  their  superior  strength,  but  chiefly, 
as  stated,  because  they  are  rather  easier  to  make  than 
arms  of  +  section  or  J_  section.  If  a  ring  of  teeth  only  is 
required  the  interior  is  formed  with  segmental  cores,  as 
in  Fig.  236.  Or  if  the  bore  is  large  and  the  arms  short, 
with  two  sets  of  cores  as  in  Fig.  237. 


MACHINE  MOULDED  GEARS 


343 


A  core  for  H  section  arms  is  seen  in  plan,  Fig.  238,  a 
section  in  Fig.  239,  and  its  grid  in  Fig.  240,  and  the  core 
also  in  Fig.  231.  The  core  is  rammed  upon  the  grid,  the 
central  part  being  composed  of  cinders,  the  main  vent 


FIG.  243. — BOARD  FOR  REVERSE  MOULD. 

being  brought  off  at  the  top,  A,  into  which  all  the 
smaller  diagonal  vents  are  carried,  as  well  as  the  vents 
from  the  cinders. 

Wheels  having  arms  of  +  or  J_  shape  can  be  also 


•oVv^V^c;-^^ 

FIG.  244. — BOARD  FOR  STRIKING  BED. 

made  in  cores,  but  the  difficulty  is  that  these  cores  have 
to  abut  and  joint  against  each  other,  while  with  the  H 
form  they  are  kept  asunder  by  an  amount  equal  to  the 
thickness  of  the  vertical  arm.  The  joints  must  abut  when 
the  edges  of  the  arm  are  convex,  Fig.  241;  also,  while  the 


344 


PRACTICAL  IRON  FOUNDING 


top  and  bottom  faces  of  the  cores  for  H  arms  always 
lie  in  the  same  plane  as  the  faces  of  the  wheel  teeth, 
those  of  the  other  sections  usually  do  not.  A  special 
bed  and  cope  then  have  to  be  struck,  and  cores  shaped 
to  correspond,  Fig.  242. 

Bevel  (fears. — Fig.  243  shows  the  method  of  making  a 
reverse  mould  for  a  bevel  wheel,  where  A  is  the  board, 
swept  round  over  a  hard-rammed  bed  of  sand,  B.  The 
edge  C  coincides  with  the  top  edges  of  the  arms,  and 
therefore  with  the  top  face  of  the  cores  of  the  bevel 
wheel,  and  D  is  the  joint  face  dividing  the  cope  from 


FIG.  245.— BOARD  FOR  STRIKING  COPE  DIRECT. 

the  drag.  Upon  this  bed,  the  board  being  removed,  the 
top  or  cope  is  rammed,  parting  sand  intervening — being 
liftered  and  vented  precisely  as  though  it  were  being 
rammed  upon  a  pattern.  This  is  then  taken  away,  and 
after  the  wheel  is  moulded  and  cored  up,  is  returned 
finally  into  position. 

On  the  removal  of  the  cope,  the  sand  which  formed 
the  reverse  mould  is  dug  out,  and  the  board  for  striking 
the  lower  face,  and  corresponding  with  the  tooth  points, 
is  attached  to  the  strap  and  slipped  over  the  bar,  Fig. 
244,  the  edge,  A,  coinciding  with  the  joint  face,  D, 
already  struck  by  the  previous  board,  and  the  bottom 
sand  swept  out.  The  tooth  block  is  then  attached 


MACHINE  MOULDED  GEARS 


345 


to  the  carrier  and  set  in  position,  and  the  ramming, 
nailing,  and  venting  proceed  generally  on  the  same 
methods  as  those  pursued  in  the  case  of  spur  wheels, 
modified  only  by  the  bevel  form.  The  alternative 
method  of  making  the  cope  by  a  direct  process  is  as 
follows:  The  centre  pillar  always  has  a  movable  collar 
fitting  over  it,  seen  in  Fig.  244;  this  collar  is  set  and 
pinched  in  such  a  position  that  its  top  face  coincides 
exactly  with  the  top  or  joint  edge  of  the  flask  on  the 
table,  as  checked  with  a  straight  edge.  The  boards,  both 
for  striking  the  cope  and  the  drag,  have  strips  nailed 


FIG.  246. — BOARD  FOR  STRIKING  BED. 


upon  them,  sometimes  one  strip  only,  sometimes  two, 
the  distance  between  the  strips  in  the  latter  case  being 
equal  to  the  width  of  the  strap,  and  the  inner  face  of 
one  strip  coinciding  with  the  joint  edge  of  the  mould. 
Figs.  245,  246,  show  the  two  boards,  Fig.  245  striking  the 
cope  direct.  It  is  clear  that  the  collar  remaining  in  the 
same  position  on  the  post,  the  joint  faces,  A,  A,  of  cope 
and  drag  will  coincide,  if  the  fittings  of  the  flasks  and 
post  are  perfect.  In  work  of  this  kind  the  flasks  have 
properly  to  be  turned  and  checked  on  their  joint  faces, 
specially  for  wheel  moulding,  but  in  the  method  first 
described  any  flasks  can  be  used,  and  the  wheel  can  be 
moulded  in  the  floor  just  as  well  as  on  a  table.  When 


346  PRACTICAL  IRON  FOUNDING 

wheels  are  moulded  in  the  floor  the  first  method  is  the 
only  one  which  can  be  adopted  without  risk  of  a  crush 
or  of  finning  occurring.  The  cope  being  rammed  in 
place  must,  when  the  mould  is  closed  for  casting,  make 
a  perfect  joint  with  the  mould  in  the  floor. 


CHAPTER  XVI 

MISCELLANEOUS  ECONOMIES — WEIGHTS  OF  CASTINGS 

ONE  of  the  duties  of  foremen  lies  in  scheming  other  ways 
of  working  than  those  which  are  regular  and  common- 
place. Occasions  arise  when,  for  economical  reasons,  it 
is  desirable  to  get  away  from  these  and  adopt  other 
methods. 

The  question  of  numbers  of  castings  required  all  alike, 
or  nearly  alike,  generally  determines  in  the  main  the 
methods  of  the  pattern-maker.  But  dimensions  also, 
whether  large,  small,  or  medium,  have  to  be  considered 
as  well.  So  also  have  shapes,  whether  irregular  or 
regular;  as  circular,  which  is  admirably  suited  for 
sweeping  up;  or  rectangular,  for  skeleton  or  sectional 
framings;  or  irregular,  which  cannot  be  so  well  treated. 
These  things  explain  why  the  ideas  of  different  men  vary 
so  much  as  to  the  most  suitable  methods  of  moulding, 
and  of  the  amount  of  assistance  which  should  be  given 
to  the  moulder  by  the  pattern  shop,  having  regard  to 
the  relative  expenses  of  each  department.  Broad  views 
and  due  balancing  of  costs  are  therefore  requisite  in  the 
conduct  of  these  departments,  which  should  never  be 
regarded  as  having  isolated  interests. 

As  there  are  several  alternative  methods  of  working 
to  achieve  the  same  results  in  the  ultimate  forms  of  cast- 
ings, we  will  consider  the  broad  divisions  of  work  just 
now  instanced,  those  of  numbers  off,  along  with  those  of 

347 


348  PRACTICAL  IRON  FOUNDING 

dimensions  and  of  shapes,  since  neither  stands  in  a 
state  of  isolation  from  the  others. 

The  usual  method  when  numbers  are  required  all  alike 
is  to  mould  from  complete  patterns,  made  exactly  like 
their  castings,  save  for  core  prints  and  cored  portions. 
And  as  the  numbers  off  increase,  more  care  is  bestowed 
upon  pattern  construction,  either  in  regard  to  the  char- 
acter of  the  wood  work,  or  in  the  abandonment  of  wood 
for  metal,  and  also  by  pressing  into  service  the  aids  to 
be  derived  from  mechanical  methods  of  moulding. 

In  the  pattern  shop  the  difference  lies  in  whatever  is 
included  in  the  terms  rough  patterns,  and  standard  pat- 
terns. This  means  a  great  deal  in  extreme  cases.  A 
rough  pattern  may  be  broken  up  immediately  that  it  is 
done  with;  and  when  that  is  the  case,  not  a  penny  more 
is  spent  on  it  than  is  absolutely  necessary.  More  work, 
of  course,  is  thrown  on  the  moulder,  who  will  have  to 
rub  his  fillets  and  the  print  portions  of  the  cores,  and 
will  often  have  to  work  with  sweeping  boards  or  skeleton 
coreboxes,  or  with  no  boxes  at  all.  Some  parts  will  be 
made  fast,  instead  of  being  dowelled,  and  the  work  will  go 
into  the  foundry  unvarnished,  and  without  rapping  or 
lifting  plates. 

On  the  other  hand,  a  standard  pattern  in  its  best  form 
will  be  perfect  in  dimensions  and  in  finish.  All  fillets 
and  radii  will  be  put  in,  cores  will  fit  their  prints  with- 
out rubbing,  every  core  will  be  made  in  its  own  box 
ready  for  use,  loose  pieces  will  be  fitted  where  there  is 
the  slightest  risk  of  the  mould  breaking  down  if  they 
were  fast;  and  they  will  be  so  fitted,  and  the  cores  also, 
that  it  will  be  quite  impossible  for  a  careless  moulder  to 
set  them  in  any  but  their  correct  positions.  There  will 
will  be  no  excuse  for  a  moulder  to  drive  his  bar  or  spike 


MISCELLANEOUS  ECONOMIES  349 

into  such  a  pattern  for  rapping  and  lifting,  for  plates  or 
straps  will  be  provided  where  required.  Care  will  be 
exercised  in  the  selection  of  timber,  which  will  be  pro- 
tected with  three  or  four  coats  of  varnish  or  paint,  well 
rubbed  down. 

Between  these  extreme  cases  most  patterns  are  made. 
Besides  these,  metal  patterns  are  substituted  generally 
for  wood  in  small  standardized  articles,  and  in  machine- 
moulded  work. 

But  as  there  are  many  classes  of  jobs  which  are  never 
repeated  in  large  numbers,  here  the  debatable  ground 
lies.  These  include  all  engine  cylinders  of  large  dimen- 
sions, large  fly-wheels,  unusual  sizes  and  shapes  of 
columns,  pipes,  and  bends,  large  drums  for  winding  and 
hauling,  big  pulleys  and  sheave  wheels  and  toothed 
gears,  either  of  which  may  be  made  in  one  of  two  or 
three  methods — namely,  from  full  patterns,  or  in  com- 
bination methods  by  the  aid  of  sweeps  in  green  sand  or 
loam  by  the  aid  of  fractional  pattern  parts,  or  of  moulds 
in  conjunction  with  such  portions  or  sections  of  patterns 
and  coreboxes  that  do  not  lend  themselves  to  methods 
of  sweeping  up.  The  mere  mention  of  these  items  will 
call  up  to  the  mind  of  a  founder  numerous  alternatives 
possible  in  the  production  of  a  mould. 

Dimensions,  we  said,  determine  methods  of  working 
to  a  large  extent.  Thus,  methods  which  are  practicable 
with  castings  measuring  from  a  few  inches  to  3  ft.  or  4  ft. 
across  are  often  unsuitable  for  those  of  larger  sizes, 
either  for  economical  or  other  reasons.  But  in  con- 
junction with  dimensions,  shapes  also  exercise  much 
controlling  influence  in  the  choice  of  methods.  Any 
symmetrical  article,  no  matter  how  large,  suggests  at 
once  the  employment  of  sweeping  up,  for  which  either 


350 


PRACTICAL  IEON  FOUNDING 


green  sand,  or  dry  sand,  or  loam,  are  often  equally  well 
adapted.  And  if  an  object  is  not  wholly  adaptable  to 
this  method  —  as,  in  fact,  few  are  —  then  it  is  always 
practicable  to  utilize  pattern  parts  or  cores  to  complete 


FIG.  247. — SKELETON  FRAME. 

the  work,  whether  done  in  green  sand,  loam  moulds,  or 
loam  patterns. 

Alternative  methods. — The  alternative  methods,  there- 
fore, of  the  foundry  may  be  very  broadly  classified  thus: 
Complete  patterns  made  in  the  ordinary  way  for  hand 
moulding.  Complete  patterns  in  which  mechanical  aids 


~  -^ 


FIG.  248. — STRICKLE. 

are  utilized.  Work  which  is  moulded  without  complete 
patterns,  which  includes  skeleton  patterns  and  moulds 
taken  from  broken  castings,  as  well  as  swept  work.  Also 
a  large  class  of  moulding  made  from  segmental  patterns, 
and  sectional  patterns  in  which  a  combination  of  several 
methods  is  utilized,  such  as  pattern  parts,  sweeps,  and 


MISCELLANEOUS  ECONOMIES 


351 


coreboxes  together.  Lastly,  there  are  devices  for  making 
moulds  differing  in  some  respects  from  their  patterns, 
which  includes  alterations  of  certain  details  only;  as  of 
patterns  in  some  degree  standard,  to  which  supple- 


Fm.  249. — STRICKLE  AND  FRAME. 

mentary  parts  may  be  fitted,  or  in  the  moulds,  in  which 
stopping-off  is  done;  or  both  devices  may  be  effected  in 
the  same  mould  in  conjunction. 


FIG.  250. — STRICKLING  A  CURVED  PLA.TE. 

In  any  of  the  methods  of  moulding,  in  which  a  com- 
plete pattern  is  dispensed  with,  there  is  a  larger  element 
of  risk  present,  that  of  inaccuracy,  than  there  is  when  a 
full  pattern  is  employed.  This  arises  in  all  work  that  is 
either  swept  up,  or  marked  out  on  sand  beds,  or  where 


352 


PRACTICAL  IRON  FOUNDING 


pattern  parts  are  bedded  in  green  sand  or  in  loam,  or 
attached  to  loam  patterns.  These  risks  the  pattern- 
maker is  expected  to  foresee  and  guard  against,  and  to 
accept  responsibility  for,  even  though  the  carrying 
through  of  the  work  lies  in  the  moulder's  hands.  As  a 


FIG.  251. — EDGES  OF  A  COREBOX  CUT  FOR  STRICKLING. 

general  rule  the  pattern-maker  has  to  spend  some  time 
in  the  foundry,  more  or  less,  during  the  progress  of  such 
jobs,  either  marking  out  centre  lines,  or  measuring-in 
parts,  or  checking  the  mould  at  certain  crucial  stages. 


FIG.  252. — EDGES  OF  Box  CUT  FOR  STRICKLING. 


Skeleton  Frames. — Take  a  large  plated  casting,  with 
or  without  flanges,  say  for  a  floorplate,  a  backplate,  a 
tankplate,  or  a  buckleplate,  to  be  moulded  from  direct, 
or  for  making  a  metal  pattern  from  for  moulding  in 
quantity.  Instead  of  battening  up  narrow  boards  to 
make  a  continuous  large  area  of,  say,  4  ft.  to  6  ft. 
square,  a  frame  only  is  made,  Fig.  247,  of  narrow  strips 


MISCELLANEOUS  ECONOMIES  353 

5  in.  or  6  in.  wide,  the  outside  dimensions  and  the  thick- 
ness only  corresponding  with  those  of  the  casting. 

The  interior  of  such  a  frame  cannot  be  rammed  on,  as 
a  solid-plated  pattern  can.  So  it  is  filled  with  hard-rammed 
sand,  strickled  off  level  with  the  top  face,  and  the  top  box 


FIG.  253.-  -STRICKLING  A  SAND  BED  FOR  PATTERN 
OR  CORE. 

is  then  rammed  on  that.  But  if  such  a  frame  is  used  for 
an  open  sand  mould,  as  many  foundry  plates  are  made, 
it  is  not  filled  up.  A  strickle  like  Fig.  248,  having  the 
depth  A  of  its  notch  equal  to  the  thickness  of  the  plate, 
strickles  out  the  sand  level  and  true  with  the  bottom  face 


FIG.  254. — LEVELLING  A  BED. 

of  the  plate,  Fig.  249.  On  the  delivery  of  the  frame  the 
mould  remains  just  as  though  a  solid-plated  pattern  had 
been  used. 

And  if  the  plate  should  be  curved  (Fig.  250),  as,  say,  for 
lighthouse,  or  tubbing  plates,  the  frame  can  be  made  as 
shown,  and  the  strickle  curved  to  correspond.  Or  a 

A  A 


354  PRACTICAL  IRON  FOUNDING 

straight  strickle  can  be  used,  sweeping  in  the  other 
direction.  The  illustration  is  given  to  show  that  a  strickle 
is  sometimes  curved ;  it  is  sometimes  also  of  an  irregular 
shape,  as  straight  and  curved  in  combination. 


FIG.  255. — THICKNESSING  FACING  SAND. 

Strickles  are  used  thus  in  corebox  work  as  well  as  in 
stopping  down  moulds  or  portions  of  the  same.  The 
curved  face  of  a  core  can  be  obtained  by  strickling  round 


FIG.  256. — SWEEPING  A  LEVEL  BED. 

the  edges  A,  A  of  the  box  in  Fig.  251,  just  as  well  as  by 
cutting  a  concave  block  of  wood  expensively,  and  fitting 
it  in  the  box.  So  can  the  edge  of  the  box  in  Fig.  252, 
while  a  bed  for  the  pattern  and  core  can  be  strickled  as 
in  Fig.  253. 


MISCELLANEOUS  ECONOMIES 


355 


Levelling  Beds. — Level  beds  are  in  constant  request, 
either  for  laying  flat  patterns  or  portions  of  patterns  on, 
the  edges  of  which  are  then  rammed  around,  also  for 
bedded-in  work,  or  in  some  cases  for  ramming  plain 
tops  on,  or  tops  on  which  otherwise  plain  facings,  lugs, 
brackets,  or  prints  have  to  be  measured  on  and  set  to 


FIG.  257.— THE  USE  OP 
SEGMENTAL  CORES. 


I 

FIG.  258.— Box  FOR  SEG- 
MENTAL  CORES. 


be  rammed  over.    Such  plain  level  beds  are  variously 
made. 

A  frequent  method  is  to  lay  two  parallel  strips  or 
straightedges  in  the  sand,  bedding  them  down  with  the 
mallet,  and  testing  with  spirit  level  along  and  across, 
and  with  parallel  strips,  Fig.  254.  Then  the  top  edges  of 
the  strips  embedded  in  the  sand  become  guides  for  a 
straightedge  or  a  plain  strickle  by  which  the  sand  is 
levelled.  At  the  same  time  venting  and  ramming  will 


356  PRACTICAL  IRON  FOUNDING 

be  done  to  form  a  firm,  suitable  bed  for  moulding  on. 
The  black  floor  sand  is  treated  first,  being  rammed, 
vented,  and  strickled  level  with  the  tops  of  the  strips, 
and  then,  if  required  for  a  mould,  a  layer  of  facing  sand 
of  about  an  inch  in  depth  is  rammed  on  this  thick- 
ness, pieces  being  put  on  the  straightedges  as  guides, 
Fig.  255.  If  the  bed  is  only  for  ramming  a  top  on,  the 
facing  sand  is  not  wanted. 


FIG.  259. — LOAM  OR  CORE  PLATES  WITH  LUGS. 

Another  way  to  make  a  bed  is  to  utilize  the  centre 
which  is  employed  for  striking  bars,  and  bolt  a  plain 
strickle  to  it,  taking  care  to  level  it  properly,  Fig.  256. 
Foundry  appliances  are  made  thus  with  little  or  no 
assistance  from  the  pattern-maker  by  the  aid  of  strickles, 
straightedges,  sweeps,  and  plain  thickness  pieces.  Thus, 
a  circular  loam  or  core  plate  can  be  swept  up  as  in 
Fig.  256,  with  a  board  notched,  as  shown  at  A,  fastened 
to  the  striking  bar.  An  alternative  method  is  to  strike 


MISCELLANEOUS  ECONOMIES 


357 


a  plain  bed  by  the  method  of  Fig.  254,  and  form  the 
edge  by  means  of  segmental  cores,  Fig.  257,  made  from 
a  box  like  Fig.  258.  If  lugs  are  wanted  for  lifting  slings, 
Fig.  259,  they  are  cut  out  of  the  cores,  or  blocks  of  wood 
are  bedded  in  if  the  plate  is  swept  up  by  the  board  in 
Fig.  256,  A. 

When  smaller  plates  are  wanted,  as  for  core  plates, 
Fig.  260,  the  moulder  borrows  a  flange  from  the  pattern 
stores  and  beds  it  in  in  open  sand,  cuts  off  some  round 


FIG.  260.— CORE  PLATE. 


FIG.  261. — BAMMING  EDGES 
AGAINST  A  STRIP. 


cores,  and  weights  them  down,  and  so  makes  his  mould. 
If  many  plates  are  wanted,  he  has  a  few  iron  patterns 
of  various  sizes  made  and  hung  up  in  the  foundry  for 
stock  service. 

Eectangular  frames  for  foundry  use,  as  for  back  plates 
of  boxes,  core  plates,  etc.,  are  made  without  even  the 
wood  framing  of  Fig.  247,  by  levelling  a  bed  by  the 
method  of  Fig.  254,  and  then  marking  out  the  size  and 
shape  of  the  frame,  and  ramming  the  edges  against  a 
strip  of  wood,  Fig.  261,  of  the  same  thickness  that  the 


358  PRACTICAL  IRON  FOUNDING 

plate  has  to  be.  The  edge  of  a  circular  plate  can  be 
rammed  with  a  piece  having  a  curved  edge,  Fig.  262. 

Plates  for  loam  work,  and  core  plates  like  Fig.  260, 
are  gaggered  over  without  aid  from  the  pattern-maker  by 
sticking  some  stout  nails  into  a  handle,  Fig.  263,  and 
pushing  these  into  the  sand  all  over  the  surface  required. 

Sweeping  in  Greenland. — In  the  simple  strickle  or 
sweeping  board  the  moulder  has  the  most  valuable 
economical  aid.  There  are,  however,  limitations  to  the 
use  of  striking  boards  in  greensand  work.  It  is  im- 
possible to  strike  up  vertical  faces,  whether  deep  or 
shallow,  in  greensand,  though  this  can  be  done  in  loam. 


TTTTT  I   f 

FIG.  262. — CURVED  STRIP.         FIG.  263. — GAGGER  PATTERN. 

A  vertical  face  of  any  depth  can  be  swept  truly  in  loam, 
provided  the  rough  coat  is  allowed  to  set  before  the 
finishing  coat  is  laid  on,  and  the  latter  is  kept  thin. 
But  greensand  is  too  loose  to  hold  together,  and  it  will 
fall  down  from  a  perpendicular  face;  and  this  must  be 
borne  in  mind  when  scheming  methods.  It  limits  such 
work  to  surfaces  that  are  horizontal,  or  of  moderate 
slope  or  curvature,  beyond  which  ramming  blocks  must 
be  used  in  conjunction  with  the  striking  boards.  And 
the  alternative  of  loam  must  not  be  rashly  resorted  to  in 
all  cases,  because  loam  is  more  costly  than  greensand, 
due  to  the  detailed  labour  of  bricking,  and  to  the  cost  of 
drying. 


MISCELLANEOUS  ECONOMIES 


359 


Another  useful  function  often  fulfilled  by  sweeping 
boards  is  the  preparation  of  faces,  either  to  lay  patterns 
on,  or  to  ram  top  parts  on.  If  we  have  a  flimsy  pattern 
to  mould  by  bedding-in,  it  will  be  next  to  impossible 
to  ram  up  such  a  pattern  truly  by  beating  it  down  and 
tucking  the  sand  under.  The  general  level  must  be  swept 


FIG.  264.  —  CONDENSER  COVER. 

up  and  the  pattern  laid  on  this,   and  any  projections 
or  recesses  be  then  attended  to  in  detail. 

The  device  of  sweeping  up  a  bed  on  which  to  ram  a 
top  has  two  advantages,  besides  the  saving  of  cost  in 
patternwork.  One  is  that  the  top  is  bound  to  go  back 
into  exactly  the  same  position  relatively  to  the  bottom 


FIG.  265. — SWEEPING  THE  MOULD. 

for  pouring.  Another  is,  that  small  pattern  parts,  as 
facings,  lugs,  bosses,  etc.,  can  be  measured  in  position 
exactly  on  the  swept-up  dummy  mould  better  than  they 
can  be  measured  into  the  actual  top.  We  will  take 
examples  illustrating  the  preceding  remarks. 

The  condenser  cover,  Fig.  264,  is  swept  in  greensand, 
Fig.  265,  in  preference  to  making  a  large  solid  pattern. 
If  the  outside  of  the  condenser  were  turned  bright,  it 


360  PRACTICAL  IRON  FOUNDING 

would  be  made  the  opposite  way  down  from  that  shown 
in  the  drawings. 

Two  boards  are  necessary,  one,  A  for  the  outer,  the 
other,  B  for  the  inner  face,  both  being  attached  to  turn 
on  any  convenient  centre  C,  such  as  that  used  for  loam 
work,  or  for  wheel  moulding.  The  board  A  for  the  top 
is  used  first,  and  having  formed  a  dummy  mould  D 
with  it,  the  top  box  is  rammed  upon  this. 

The  question  may  be  asked,  Why  not  strike  the  top  part 
direct  with  a  board  shaped  like  a  loam  board — that  is, 
cut  the  opposite  way  to  A?  The  answer  is  that  when 
greensand  is  being  rammed  it  is  easier  to  ram  it  wholly 
without  combination  and  interference  with  the  work  of 
sweeping  up.  Another  good  reason  is  that  the  top  being 
rammed- in  place,  goes  back  exactly  right,  guided  by 
the  stakes  by  which  it  is  set  on  the  lower  mould  in  the 
floor,  or  by  the  pins  in  a  box. 

After  the  top  has  been  rammed  and  removed,  the 
bottom  E  is  swept  out  with  its  board  B.  The  shoulder 
F,  though  shallow,  will  have  to  be  made  good  with  a 
sweep. 

The  moulding  of  fly-wheels  with  wrought-iron  arms, 
in  the  absence  of  a  full  pattern,  requires  two  boards  and 
a  sweep.  The  latter  is  of  the  same  section  as  the  rim 
of  the  casting,  besides  which  it  carries  arm  bosses  and 
boss  prints  (see  p.  170). 

Moulds  modified  from  Patterns. — In  nearly  all  shops  a 
good  deal  of  makeshift  work  is  done.  It  includes  altera- 
tions in  the  depth  of  teeth  of  gear  wheels,  in  rims,  in 
thicknesses,  in  hubs,  in  the  casting  of  wheels  of  dif- 
ferent kinds  and  dimensions  together,  and  many  other 
matters.  Some  alterations  can  be  effected  in  the  foundry 
without  alterations  in  the  pattern. 


MISCELLANEOUS  ECONOMIES  361 

Changing  Depth  of  Patterns. — Suppose  it  often  happens 
that  a  gear  wheel  has  to  be  cast  either  shallower  or  deeper 
than  the  pattern  wheel.  In  the  first  case  it  will  be  stopped 
off;  in  the  second,  drawn.  The  pattern,  therefore,  would 
not  be  cut  in  the  first  place,  nor  increased  in  thickness 
in  the  second.  But  drawing  and  stopping  off  affect 
other  parts  besides  the  teeth.  Obviously,  if  a  pattern 
is  drawn  in  the  sand,  the  depth  or  thickness  of  arms, 
ribs,  and  boss  will  be  increased  by  as  much  as  the  teeth. 
If  it  is  stopped  off,  the  depth  or  thickness  of  these  will 
be  reduced  by  as  much  as  the  teeth.  This  in  some 


FIG.  266. — STOPPING  OFF  A  WHEEL. 

cases  involves  a  good] deal  of  work  to  be  done  all  over 
the  mould — so  much,  in  fact,  that  if  several  castings 
altered  thus  were  wanted,  it  would  generally  be  cheaper 
to  make  a  new  pattern,  or  to  have  the  wheels  moulded 
by  machine.  We  will  take  the  two  methods,  and  show 
in  detail  what  has  to  be  done  in  each  case. 

Stopping  Off. — Take  a  wheel  of  the  commonest  type 
moulded  from  a  complete  pattern,  one  with  arms  of 
T- section.  Say  the  wheel  is  3  in.  deep  and  it  has  to  be 
stopped  off  to  2£  in.  The  first  thing  is  to  make  a  small 
strickle,  Fig.  266,  A,  and  in  perspective  in  Fig.  267, 
which  after  the  wheel  has  been  rammed  up  will,  on  being 
worked  round  from  its  upper  face  all  around  the  teeth, 
form  a  new  joint  face  -f  in.  below  that  made  by  the 


362 


PRACTICAL  IRON  FOUNDING 


pattern.  So  far  so  good:  but  then  it  follows  that  the 
arm  mould  is  still  f  in.  higher  than  the  new  joint  face. 
Either  the  arms  must,  therefore,  be  cut  out  entirely, 
and  a  new  pattern  arm  moulded  by  bedding-in,  or  the  in- 
terior must  be  wholly  formed  anew 
by  means  of  cores;  or  alternatively 
the  wheel  must  not  be  strickled  on 
the  top  face,  but  on  the  bottom, 
before  it  is  turned  over,  and  the 
vertical  arms  must  be  stopped  off. 

This  last  is  always  the  better  plan 
to  adopt  in  the  case  of  a  wheel  of 
the  type  shown.  Fig.  268,  therefore, 
shows  the  stage  of  moulding  at  which  the  strickle  is  used—- 
that is,  after  the  ramming  up  of  the  wheel  in  the  bottom 
box,  previous  to  turning  the  latter  over  to  take  the 
cope.  It  necessitates,  however,  a  three-part  flask,  because 
now  there  will  be  two  joints  at  a  and  at  b  respectively, 


FIG.  267.— USING  A 
STRICKLE. 


=1 


illL,; 

mm 


FIG.  268. — STOPPING  OFF  A  WHEEL. 


instead  of  one  at  b  only,  as  in  the  ordinary  way  of  moulding 
such  a  pattern.  The  sloping  joint  at  a  is  now  strewn  with 
parting  sand,  and  the  second  portion  of  the  box,  a  bottom 
part,  is  put  on  and  rammed  over  it.  Then  the  mould  is 
turned  over,  the  cope  put  on  the  joint  face  b,  and  rammed, 
and  removed  (it  has  been  only  temporarily  rammed  in 
Fig.  268);  the  pattern  drawn,  and  the  boxes  parted  at  a. 


MISCELLANEOUS  ECONOMIES 


363 


Fig.  269  shows  the  bottom  part  of  the  mould  as  it  appears 
at  this  stage.  Now  all  the  tooth  spaces  c,  which  of  course 
are  f  in.  deep,  are  filled  up  with  sand  level  with  the 
joint  face.  Also  the  supplementary  portions  of  the  ribs 
are  filled  up  with  sand  to  the  dotted  lines  and  made 


FIG.  269.  —  STOPPING  OFF  A  WHEEL. 

good  with  a  pattern  rib.  The  hub  also  is  filled  up  with 
a  pattern  boss.  This  completes  the  stopping  off,  which 
is  done  neatly  and  with  comparatively  little  trouble. 

Pattern  of  Plated  Type.  —  If  the  pattern  is  a  disk  or 
plated  type  of  wheel,  Fig.  270,  then  it  is  unnecessary  to 
interfere  with  the  disk  at  all.    But 
the  disk  will  be  out  of  centre  in  the 
shallower  wheel.    In   the  event  of 
this  being  considered  objectionable, 
it  is  practicable  to  strickle  down  a 
new  joint  from  each  tooth  face,  the 
depth  of  each  being  equal  to  half 
the  total  reduction  required.    Then 
in  the  bottom   the   supplementary 
portions  of  the  teeth  would  be  filled  up  with  sand  in  the 
way  just   noted,    and  on   the  top   the   cope  would   be 
lowered  on  the  new  joint  formed  directly  by  the  strickle. 

Drawing.  —  Coming  next  to  the  work  of  drawing  a 
wheel,  and  making  use  of  the  same  examples  as  before, 
the  ramming  is  done  in  the  usual  way.  The  wheel  is  then 
rapped  and  withdrawn.  The  distance  to  which  it  is  with- 


270  _STOPPING 
opp  A  PLATED 
WHEEL. 


364  PRACTICAL  IRON  FOUNDING 

drawn  at  this  stage  is  equal  only  to  the  increased  depth 
required.  The  exact  depth  is  best  gauged  by  means  of  three 
or  four  thickness  strips  A,  Fig.  271,  laid  on  the  joint  face 
of  the  mould  close  to  the  pattern.  The  ramming  is  now 
continued  up  to  the  top  face  a  of  the  wheel.  At  this  stage 
the  cope  is  put  on  and  rammed,  and  lifted  off.  Then  the 
pattern  is  withdrawn  wholly  from  the  mould,  leaving  the 
teeth  deeper  than  the  pattern.  It  often  happens  that 
some  slight  fracture  of  the  sand  will  occur  in  doing  this 
work,  and  then  three  mending-up  teeth  are  made  and 
used  of  the  total  depth  of  the  drawn  teeth. 

Objectionable  Results. — The  flat  arms  obviously  become 


I  •<-- 1---4---' 

FIG.  271. — DRAWING  A  WHEEL. 

increased  in  depth  by  this  operation,  and  a  single  stop- 
ping-off  arm,  Fig.  272,  is  made  and  used  to  reduce  the 
moulded  arms  to  the  right  thickness.  The  surfaces  of  the 
mould  are  hatched  over  with  the  trowel,  and  the  pattern 
arm  being  put  in  place,  sand  is  tucked  underneath  and 
made  up  good  to  the  under-face  of  the  pattern  arm.  The 
hub  is  similarly  treated.  All  this  is  troublesome  and 
tedious,  and  makes  much  mess  in  the  mould,  especially 
at  the  junctions  of  the  separate  arms  with  the  boss  and 
with  the  rim. 

In  the  case  of  a  plated  wheel  drawn,  the  surface  of 
the  moulded  plate  is  made  good  with  sand  to  its  proper 
thickness. 

Broken  Castings. — These  are  frequently  utilized  for 
moulding  from,  instead  of  making  expensive  patterns. 


MISCELLANEOUS  ECONOMIES 


365 


Customers  sometimes  expect  a  moulder  to  do  marvels 
with  a  broken  casting.  They  sublimely  ignore  such 
matters  as  delivery,  roughness  of  surface,  recessed  por- 
tions, holes,  shrinkages,  and  the  rest.  All  they  can  say 
is  that  they  want  a  new  casting  without  going  to  the 
expense  of  a  pattern,  and  the  moulder  is  expected  to 
furnish  it. 

Almost  any  casting  can  be  moulded  from,  just  as 
almost  any  pattern  can  be;  but  the  question  always 
arises  whether  it  pays,  having  regard  to  the  amount  of 
work  required  to  make  it 
mouldable,  and  to  the  extra 
time  occupied  in  the  mould- 
ing. These,  together  with 
the  numbers  required,  de- 
termine the  alternative  of 
moulding  from  old  castings, 
or  of  making  new  patterns. 
The  question  is  a  very  wide 
one,  especially  in  jobbing 
shops,  and  it  can  only  be 
settled  after  a  considera- 
tion of  the  pros  and  cons  in  every  individual  case.  These 
include  the  nature  of  the  surfaces,  the  presence  of 
broken  parts,  shapes  suitable  or  otherwise  for  delivery, 
including  coring,  how  to  joint,  shrinkages,  the  amount 
of  wear  which  a  casting  has  sustained,  facility  for  getting 
it  out  of  the  sand,  and  allowances  for  tooling. 

The  first  thing  to  do  with  a  casting  to  be  moulded 
from,  is  to  clean  it  thoroughly,  which  is  generally  done 
by  making  it  red  hot  in  a  clean  coke  fire  in  order  to  burn 
off  all  grease,  oil,  and  dirt.  When  cold  it  is  brushed  with 
card  wire  or  rubbed  with  emery  cloth,  and  is  then  taken 


FIG.  272.— ARM  FOR 
STOPPING  OFF. 


366 


PRACTICAL  IEON  FOUNDING 


in  hand  by  the  patternmaker  to  prepare  it  for  moulding. 
We  will  note  the  points  to  be  attended  to  in  various 
castings  by  some  selected  examples. 

Fig.  273  shows  a  double  bracket  fractured  at  K.  This 
can  be  moulded  from  very  well  without  making  a  new 
wooden  pattern  by  having  a  corebox  to  take  out  the 
interior  space  A,  using  a  print  for  the  purpose  a.s  shown. 
The  thickness  of  the  core  will  be  the  same  as  the  width 
B,  but  the  length  C  and  width  D  of  the  print  are  unirn- 


FIG.  273. — BROKEN  BRACKET  PREPARED  FOR 
MOULDING  FROM. 

portant  so  long  as  there  is  sufficient  bearing  to  carry  the 
core  without  crushing  the  edges  of  the  bracket  mould. 

Frequently  the  bolt  holes  are  wanted  cored.  Pocket  or 
drop  prints  have  to  be  put  on  at  E,  E  to  core  these.  The 
prints  may  be  secured  sometimes  by  plugging  up  the  old 
holes  with  wood  and  nailing  the  pocket  prints  to  these 
plugs.  If  this  is  not  sufficient,  small  holes  may  be  drilled 
in  the  casting  and  plugged  with  wood  to  receive  the  nails 
from  the  prints.  Eound  prints  F,  F  will  be  driven  into 
the  holes  in  the  bosses,  giving  -J-  in.  allowance  for  boring. 
The  moulding  will  be  done  with  the  bosses  in  bottom 
and  top — that  is,  as  tho  right-hand  figure  lies — and  the 


MISCELLANEOUS  ECONOMIES 


367 


parting  in  the  mould  will  be  along  the  top  face  of  the 
print  A.  A  corebox  (Fig.  274)  will  be  made  to  fill  up  the 
impression  of  the  main  print  for  coring  out  the  space  A  , 
and  the  small  facing  bosses  will  be  put  in  the  core.  The 
thickness  *B  of  the  box  corresponds  with  the  thickness  B 
of  the  print  in  Fig.  273,  the  length  C  with  C  in  that 
figure,  and  the  width  D  with  the  width  D.  The  time 
saved  is  that  of  making  the  whole  of  the  pattern  proper, 
omitting  the  print  and  corebox,  which  would  have  to  be 
done  if  a  new  wood  pattern  was  made. 

With  regard  to  shrinkage,  if  the  height  of  the  casting 
from  foot  to  centre  is  im- 
portant, then  it  is  usual  to 
attach  a  thickness  piece  to 
the  face  G  of  the  foot,  to 
allow  for  shrinkage,  £,  fV, 
or  -J-  in.,  as  may  be  required. 
In  small  patterns  sufficient 
allowance  may  of  ten  be  given 
by  extra  rapping. 

Broken  castings  are  gen- 

erally varnished  before  being  moulded.  Vertical  faces, 
if  rough,  must  be  smoothed  with  a  file;  the  flat  faces 
need  not  be.  If  the  vertical  faces  are  very  rough,  some 
beeswax  may  be  worked  in  and  smoothed  over,  or  finely- 
powdered  chalk  mixed  with  varnish,  and  when  hardened, 
glass-papered  and  varnished.  These  applications  fill  up 
the  hollow  parts  of  the  rough  surfaces. 

Fig.  275  shows  how  a  broken  pipe  bendjis  prepared  for 
moulding  from.  The  ends  are  plugged  with  round  prints, 
and  the  broken  parts  are  laid  together  in  the  mould 
without  any  fastening,  the  moulder  seeing  that  they  do 
not  shift  during  ramming. 


FIG.  274.  —  CORE  Box  FOR 
BRACKET. 


368 


PRACTICAL  IRON  FOUNDING 


Fig.  276  shows  how  a  common  rope  or  sheave  pulley  is 
prepared  for  moulding  from.  A  block  of  wood  is  fitted 
roughly  to  the  interior  of  the  groove,  simply  to  assist  in 
steadying  the  print  A,  which  is  fitted  against  the  edges 
of  the  pulley  rim,  its  thickness  coming  flush  with  the 
outside  of  the  rim  on  top  and  bottom.  This  sweep  is 
worked  round  the  rim,  being  kept  level  by  the  small 
battens,  and  rammed  in  successive  stages,  so  forming  a 
print  for  segmental  cores,  by  which  the  interior  shape  of 

the  rim  is  produced.  Be- 
fore any  of  this  is  done, 
the  arms  are  rammed  up 
in  the  bottom  and  top,  a 
joint  face  being  formed 
flush  with  the  top  edge  7> 
of  the  rim.  Then  after  that 
the  sweeped  print  A 


FIG.  275. — BROKEN  PIPE  PRE- 
PARED FOR  MOULDING. 


is 

worked  round,  and  when 
the  cores  are  laid  in  they 
come  flush  with  the  joint 
face,  which  lies  outside 
them.  The  corebox  is  of 

the  same  section  as  the  interior  of  the  rim,  plus  the 
added  space  required  to  fill  up  the  print  impression. 

A  point  that  is  very  essential  when  taking  moulds 
from  broken  castings  is  that  the  parts  must  be  laid 
accurately  in  their  relative  positions  for  ramming. 
Straightedges,  winding  strips,  and  the  rule  must  be  used 
to  test  this.  It  is  easy  when  ramming  a  fragmentary 
casting  in  the  floor  to  get  the  parts  out  of  truth,  and  so 
make  crooked  and  winding  castings.  In  many  cases  a 
levelled  bed  of  sand  will  afford  accuracy  to  the  pieces  in 
one  plane.  If  the  work  is  not  absolutely  level,  but  is  so 


MISCELLANEOUS  ECONOMIES 


369 


in  the  main,  then  the  level  bed  of  sand  is  necessary,  and 
holes  are  dug  in  it  to  take  those  parts  that  project 
beyond  the  general  plane. 

Among  the  simplest  castings  that  can  be  moulded 
from  are  bearings  of  ordinary  kinds.  The  only  difficulty 
is  in  adding  the  due  allowance  for  machining,  as  boring 
and  facing.  In  very  small  work  a  slight  increase  in  the 
size  can  always  be  made  by  excessive  rapping.  Or  a  care- 
ful moulder  can  scrape  out  the  mould  a  little  larger  with 
his  trowel  or  cleaner,  with  or  without  the  aid  of  thick- 
ness strips  laid  in  the  portion  to  be  machined.  The  safer 
way,  however,  is  to  line  up  the  portions  which  have  to 


FIG.  276. — SHEAVE  PREPARED  FOR  MOULDING. 

be  faced  with  sheet  lead,  or  with  thin  leather  or  wood, 
and  this  must  be  done  in  many  jobs.  The  linings  need 
not  necessarily  be  fastened  to  the  castings.  If  laid  against 
them  in  the  mould  that  is  sufficient. 

A  common  belt  pulley,  with  single  arms,  can  be  easily 
moulded  from.  The  allowance  for  turning  is  given  by 
laying  thin  strips  of  wood  around  the  rim,  and  the 
moulder,  guided  by  the  thickness  of  these,  scrapes  out 
the  mould  so  much  larger  than  the  broken  casting.  But 
a  wide  pulley,  with  double  arms,  cannot  be  moulded 
without  making  a  corebox  to  take  out  the  space  between 
the  arms,  though  all  the  rest  will  deliver  freely.  It  would, 
however,  cost  less  to  make  a  corebox  than  to  make  an 

BB 


370  PRACTICAL  IRON  FOUNDING 

entire  pulley  pattern.  But  many  shops  keep  pulley  pat- 
tern rings  and  sets  of  arms  of  all  sizes,  and  then  it  is 
cheaper  to  mould  from  one  of  these  than  to  make  a 
corebox  for  the  broken  casting. 

Using  broken  castings  as  patterns  frequently  gives 
more  trouble  in  making  sand  joints  than  if  wooden  pat- 
terns were  made.  Speaking  very  generally,  the  joints  in 
pattern  and  mould  coincide,  with  some  slight  variations. 
But  all  broken  castings  are  destitute  of  any  joints,  and 
then  there  must  be  the  alternative  in  some  cases  of 
using  cores,  in  others  of  making  sand  joints,  and  lifts 
against  faces  frequently  vertical,  with  consequent  tearing 
up  of  the  sand;  or  drawbacks  may  be  used.  Thus  in 
Fig.  273  the  sand  must  be  lifted  away  from  the  vertical 
faces  above  the  main  core  print  A.  In  a  pattern  these 
portions  would  be  left  loose.  The  wood  pattern  for  the  pipe 
in  Fig.  275  would  be  jointed  along  the  centre.  Moulded 
from  the  undivided  casting,  portions  of  the  top  sand  are 
bound  to  fracture,  so  that  more  work  is  thrown  on  the 
moulder  in  mending  up  than  when  moulding  is  done 
from  properly  jointed  patterns. 

When  allowances  for  shrinkage  are  excessive,  due  to 
the  large  dimensions  of  a  casting,  it  results  in  undue 
thickening  up  of  the  parts — the  plates  or  flanges — to 
which  the  thickening  pieces  are  attached.  Sometimes 
this  does  not  matter,  but  often  it  is  very  objectionable, 
as  in  the  rim  of  a  light  pulley  or  the  flanges  of  light 
plates.  The  due  proportioning  of  metal  is  interfered 
with,  and  in  some  cases  fracture  is  liable  to  occur.  If 
such  is  the  case,  then  the  broken  work  must  not  be 
moulded  from.  Sand  can  be  scraped  away  without  much 
difficulty,  but  it  is  very  troublesome  and  unsafe  to  put  it 
on  in  quantity  in  parts  of  a  mould.  It  can  only  be  done 


MISCELLANEOUS  ECONOMIES  371 

by  hatching  up  the  surface,  moistening  with  the  swab, 
and  if  the  substance  is  sufficient,  nailing  also.  Then,  after 
all,  there  is  risk  of  scabbing  or  washing  away  of  portions 
of  the  added  sand.  So  that,  unusual  cases  apart,  the  work 
of  the  moulder  is  restricted  to  scraping  moulds,  mending- 
up  only  being  done  where  the  sand  has  broken  down. 

Often  broken  castings  are  also  worn  or  corroded  badly 
in  places.  Sometimes  the  moulder  can  make  these  parts 
good  by  scraping  the  mould ;  but  as  a  rule  the  pattern- 
maker takes  charge  of  this,  making  good  the  worn  por- 
tions with  wood,  nailed  or  screwed  to  plugs  in  drilled 
holes,  or  cemented  on,  or  simply  laid  in  place  next  the 
casting  in  the  mould.  Small  parts  also  broken  off  are 
lost,  and  then  the  patternmaker  has  to  supply  them. 

There  is  therefore  more  in  this  question  of  utilizing 
broken  castings  than  appears  at  first  sight.  A  foreman 
must  be  able  in  any  given  case  to  determine  when  old 
castings  should  be  utilized,  or  the  alternative  of  new 
patterns  followed.  The  device  is  often  highly  economical ; 
in  other  cases  it  is  expensive  and  unsatisfactory. 

Burning  on. — This  signifies  the  mending  of  fractured 
castings,  or  imperfect  castings  due  to  incomplete  running, 
by  a  process  of  autogenous  soldering  of  metal  to  metal. 
It  is  simply  this,  that  sufficient  molten  metal  is  poured 
over  the  surface  against  which  the  union  has  to  be 
effected  until  local  fusion  has  taken  place.  Then  the 
pouring  is  stopped,  and  the  casting  is  afterwards  as  strong 
there  as  elsewhere.  The  danger  is  lest  the  local  increase 
in  temperature  should  cause  fracture  of  the  casting  to 
occur  in  the  vicinity. 

Before  commencing  to  burn  on,  the  casting  is  heated 
in  the  drying  stove,  brought  out,  imbedded  in  the  floor, 
and  the  particular  locality  where  the  fusion  is  to  take 


372  PRACTICAL  IRON  FOUNDING 

place  is  heated  with  red-hot  weights  placed  in  proximity 
thereto.  This  is  done  to  diminish  risk  of  fracture.  Sand 
or  loam  cake  is  built  up  around  the  spot  where  the  new 
portion  has  to  be  burned  on,  and  is  shaped  into  the  par- 
ticular outline  required.  A  gutter  or  channel  is  cut  lead- 
ing away  from  this.  The  molten  metal  is  now  poured 
gently  and  slowly  over  the  fractured  surface,  and  al- 
lowed to  run  away  through  the  gutter.  The  heat  of  the 
metal  soon  produces  fusion  of  the  surface,  and  when  the 
moulder  learns  by  trial  with  the  end  of  a  rod  that  fusion 
has  taken  place,  he  ceases  pouring.  To  burn  on  only  a 
few  pounds  of  metal  several  hundredweights  have  to  be 
run  over  the  surface  into  the  gutter.  This  is  broken  up 
afterwards. 

Weights  of  Castings. — The  only  correct  way  of  calculat- 
ing the  weight  of  metal  in  a  casting  is  to  compute  the 
number  of  cubic  inches  which  it  will  contain,  and  multiply 
these  by  a  number  expressive  of  the  weight  of  a  unit 
volume  of  the  kind  of  metal  used.  The  latter  is  the  cubic 
inch — only  in  very  heavy  work  is  the  cubic  foot  employed. 
The  following  table  gives  the  weight  of  a  cubic  inch  of 
the  common  metals  and  alloys. 

Weight  of  cub.  in. 
Metal  or  Alloy.  in  Ib.  avoir. 

Cast  iron 0.263 

Wrought  iron 0.281 

Steel 0.283 

Copper 0.3225 

Brass 0.3037 

Zinc 0.26 

Lead 0.4103 

Tin 0.2636 

Mercury 0.4908 


WEIGHTS  OF  CASTINGS 


373 


The  simplest  forms  for  calculation  are  those  of  rect- 
angular outlines.   After  these  come  circular 'sections  and 


r 


v'.o 

B 


1 


u    u    u    u 


u    u 


_  n  _  n  _  n  _  n  _  n  .  n    n 


&    ^ 


FIG.  277.— TANK  PLATE. 

regular  curves,  and  then  the  numerous  irregular  outlines 
which  occur  in  castings. 


}  (*} 

M 

i}    ( 
1     \    } 

FIG.  278. — FLANGE  AND  BRACKETS  OF  PLATE. 

As  an  example  of  the  first,  take  a  common  tank  plate 
(Figs.  277,  278).  The  details  of  this  are  wholly  rectangu- 
lar, and  it  is  only  necessary  to  multiply  length  by  breadth 
by  thickness  of  the  various  details,  as  follows. 


374  PRACTICAL  IRON  FOUNDING 

In  estimating  weights  it  is  well  to  set  down  all  the 
details  in  a  weight  book,  in  ink,  for  future  reference,  if 
required,  thus;  the  quotients  in  cubic  inches  being  added 
as  reckoned  subsequently: 

Cub.  in. 
A  I  plate,  4  ft.  X  4  ft.  x  fin =1440 

B,  B,  2  flanges,  4  ft.  x  2|  in.  x  f  in.      .     .   =   180 

C,  <7,  2  flanges,  3  ft.  10J  in.  x  2J  in.  x  £  in.   =   174 

^—  x  21  in 
D,  28  brackets,  -   — ~-  -  xf  in. .     .   =     65.5 

1859.5 
Deduct  32  bolt-holes,  f  in.  xf  in.  xf  in.  =  13.5  cub.  in. 

The  whole  of  the  items  being  thus  set  down  at  first, 
there  is  no  risk  of  omitting  anything  afterwards.  The 
details  of  the  computations  need  not  be  given,  but  the 
results  only.  The  use  of  the  reference  letters,  A,  B,  and 
(7,  enables  one  to  see  at  a  glance  whether  any  item  has 
been  calculated  or  not. 

Adding  these  figures  we  get  1859.5  total  cubic  inches. 
Deducting  the  32  bolt-holes  therefrom,  we  obtain  1859.5  — 
13.5  =  1846  cubic  inches  as  the  solid  contents  of  the  tank 
plate. 

Angles  or  fillets  are  usually  cast  round  the  flanges  and 
brackets  and  they  will  hardly  be  less  than  £  or  f  in.  on 
the  sides.  But  instead  of  reckoning  these  up,  simply  knock 
out  the  13.5  Ib.  weight  of  metal  taken  out  by  the  holes, 
allowing  that  much  for  the  added  weight  of  angles.  So 
that  we  say  that  there  are  1859.5  cubic  inches  in  the 
tank  plate,  and  the  decimal  can  be  omitted. 

To  bring  1859  cubic  inches  into  pounds  multiply  by 
the  number  representing  the  weight  of  a  cubic  inch  of 


WEIGHTS  OF  CASTINGS  375 

cast  iron  given  in  the  table,  p.  372  =  0.263  =  489.9  lb., 
say  490  lb. 

In  connection  with  the  plate  the  frequent  and  consider- 
able divergence  between  the  estimated  and  actual  weights 
may  be  mentioned.  A  plate  of  this  or  of  kindred  type  is 
certain  to  exceed  the  calculated  weight  unless  precautions 
are  taken  to  prevent  it.  The  reason  is  mainly  because  of 
the  broad  superficial  area  over  which  enormous  liquid 
pressure  takes  place  at  the  time  of  casting,  causing  the 
top  flask  to  rise,  with  a  consequent  thickening  of  the 
casting.  If  the  flask  is  rather  light,  and  the  weighting  or 
loading  down  insufficient,  the  evil  will  be  magnified;  and 
if  the  moulder  rams  too  lightly,  or  indulges  too  much  in 
scraping,  rubbing,  and  sleeking,  the  thickening  will  be 
still  further  increased.  I  have  seen  plates  come  out  fully 
fV  in-  thicker  in  the  central  parts  than  the  pattern,  with 
the  addition  of  something  like  ^  cwt.  to  the  calculated 
weight.  So  it  by  no  means  follows  that  when  castings 
are  found  to  vary  considerably  from  the  calculated 
weights,  the  calculations  themselves  are  incorrect.  It  is 
specially  in  castings  of  this  general  type  that  we  have  to 
be  on  our  guard.  All  broad  flat  areas  tend  to  increase  of 
thickness,  while  in  the  case  of  vertical  webs,  however 
deep,  there  is  little  or  no  difference  in  the  thicknesses  of 
pattern  and  casting  observable. 

Actually,  some  allowance  is  made  in  the  pattern  shop 
in  cases  where  experience  shows  that  a  casting  will  come 
out  thicker  than  the  pattern.  If  a  casting  is  liable  to 
gather  by  TV  in.,  the  pattern  is  made  ^F  in-  thinner;  if 
-J-  in.  thicker,  then  -J  in.  less.  A  4  ft.  tank  plate  pattern 
should  be  made  fully  -XV  in.  less  in  thickness  than  the 
thickness  given  on  the  drawing;  and  if  the  plate  were 
larger  than  4  ft.,  thinner  still. 


376 


PRACTICAL  IRON  FOUNDING 


The  fly-wheel  shown  in  half  plan  in  Fig.  279,  and  in 
section  in  Fig.  280,  is  an  example  of  a  circular  casting. 
At  the  section  to  the  left  is  shaded  regularly,  that  to  the 
right  being  shaded  to  illustrate  how  it  is  divided  into 
separate  sections  for  convenience  of  calculation.  Taking 
the  rim  A,  first.  Obtain  the  mean  circumference,  and  then 
reckon  the  rim  as  a  straight  strip  of  metal.  The  outside 


FIG.  280. 
FLY-WHEEL. 

diameter  is  3  ft.,  the  thickness  l-|-in.  The  inner  diameter 
is,  therefore,  2  ft.  9  in.,  and  the  mean  diameter  will  be 
2  ft.  10!  in-  Set  down  the  first  item  of  measurement  of 
the  wheel  in  tabular  form  as  given  on  p.  377. 

The  inner  ring,  J5,  has  its  section  concave  and  convex, 
and  by  reducing  this  to  a  plain  rectangle  the  concave 
portion,  will  about  compensate  for  the  convex  edges.  This 


WEIGHTS  OF  CASTINGS  377 

is  sufficiently  approximate;  and  time  will  only  permit  of 
practical  approximations  in  all  work  of  this  character.  So 
we  reduce  the  ring,  B,  to  a  rectangular  section.  Its  outer 
diameter  is  2  ft.  9  in.,  and  it  is  1£  in.  wide;  therefore  its 
mean  diameter  is  2  ft.  71  in.,  and  its  section  1-J  x  1^  in. 
We  set  down  B  accordingly  in  the  table.  The  central  boss, 
C,  in  like  manner  has  a  mean  diameter  of  3f  in.,  and  a 
section  of  6  x  1^  in.  The  ring,  D,  around  the  boss  has 
a  mean  diameter  of  6  in.,  and  a  section  of  H  x  li  in- 

There  are  now  six  arms,  E,  of  elliptical  section.  By 
making  the  necessary  deductions  at  circumference  and 
centre,  we  get  six  plain  straight  arms,  each  11£  in.  long. 
The  mean  section  of  the  ellipse  at  the  centre  is  2  J  x  If  in. 
To  obtain  the  area  of  an  ellipse,  the  product  of  the  two 
dimensions  is  multiplied  by  0.7854.  So  we  set  down  the 
arms,  E9  as  shown  in  the  table.  Every  item  now  is  tabu- 
lated except  the  radii,  c,  by  which  the  arms  merge  into 
the  rim  and  boss,  and  these  can  be  neglected,  or  a  small 
allowance  lumped  on  for  them.  Now: 

A,  I  ring  2  ft.  10J  in.  dia.  x  41  in.  x  1£  in.      .  = 

B,  1  ring  2  ft.  7%  in.  dia.  x  11  in.  x  H  in.  .     .  = 

C,  1  ring  3f  in.  dia.  x  6  in.  x  1^  in.   .     .     .     .  = 

D,  1  ring  6  in.  dia.  X  1^  in.  x  1^  in = 

E,  6  arms  11£  in.  long  x  2f  in.  x  If  in.  x  0.7854  = 

1279.2 

The  circumference  of  A  in  the  table,  of  2  ft.  10^  in. 
=  34.5  in.  x  3.14159  =  108.3  in.  But  it  is  not  usual  or 
necessary  to  take  the  trouble  of  calculating  circumfer- 
ences or  areas,  because  tables  of  these  are  given  in  en- 
gineers' books  of  reference.  Multiplying  108.3  in.  by 


378 


PRACTICAL  IRON  FOUNDING 


4.5  by  1.5  in.  we  obtain  761  cubic  inches  in  the  rim, 
and  set  that  down  opposite  A  in  the  table,  p.  377. 


FIG.  281. — SECTION  OF  BEVEL  WHEEL. 

In  a  similar  way  we  compute  the  number  of  cubic 
inches  in  each  item,  and  record  the  results  thus  found 
in  the  table,  as  indicated. 


FIG.  282. — PLAN  OF  WHEEL  ARMS. 

The  total  is  1279.2  cubic  inches.  Multiplying  by 
0.263  we  get  336  Ib.  weight  of  wheel,  or  3  cwt. 

The  next  illustration  is  a  bevel  wheel,  Figs.  281,  282. 
There  rs  a  major  pitch  diameter,  A,  and  a  minor  pitch 
diameter,  B.  In  estimating  the  sectional  areas  of  the  rings 


WEIGHTS  OF  CASTINGS  379 

formed  by  teeth  and  rim  we  take  as  our  basis  the  mean 
diameters,  C,  and  I),  thus: 

Instead  of  reckoning  the  sectional  contents  of  a  single 
tooth  and  multiplying  by  the  number  of  teeth  in  the 
wheel,  we  make  a  ring  of  the  teeth.  Take  the  "  face  " 
portion — beyond  the  pitch  line  (shaded  at  a,  right-hand 
and  in  plan) — and  turn  this  over  between  the  "  flank  " 
portions — below  the  pitch  line  (a,  left-hand  in  figure  and 
in  plan).  Say  the  tooth  is  1  in.  long  (mean  dimensions 
are  taken  to  average  the  taper  in  the  rim),  and  the  flank 
portion  T9¥  in.  long,  as  figured  in  section.  Turning  over 
a  to  a,  we  have  a  ring  of  metal  TV  in.  thick,  instead  of 
^  in.,  which  would  be  one-half  the  total  length  of  tooth. 
But  the  "  flank  clearance  "  between  tooth  face  and  tooth 
flank  will  be  set  off  against  this,  so  that  -£$  in.  thickness 
of  ring  will  be  very  approximately  correct.  So,  instead 
of  taking  the  mean  pitch  diameter,  Ct  of  the  wheel  for 
the  diameter  of  the  ring  of  teeth,  we  take  the  mean  dia- 
meter, E,  of  the  ring  of  metal  T7F  in.  in  thickness.  This 
is  1  ft.  lOf  in.  diameter.  We  set  down,  then,  the  first 
item  as  a  ring,  a',  1  ft.  lOf  in.  diameter  by  £$•  in.  mean 
thickness  by  4  in.  width  of  face  of  tooth. 

Cub.  in. 

a  1  ring  1  ft.  lOf  in.  dia.  X  rv  in.  x  4  in.  =  125 
b  1  ring  1  ft.  10  in.  dia.  x  f  in.  x  4  in.  .  =  207 
c  1  boss  8J  in.  dia.  X  5^  in.  x  1£  in.  .  .  =  72 
d  6  arms  6£  in.  long  x  2f  in.  x  f  in. .  .  =  76 
e  6  arms  8-J-  in.  long  x  3f  in.  x  f  in.  .  .  =  119 


599 


The  rim,  b,  of   the  wheel  has  a  mean  diameter  of 
1  ft.  10  in.,  and  its  mean  thickness  is  f  in.,  and  width 


380  PRACTICAL  IRON  FOUNDING 

4  in. ;  we  set  it  down  accordingly.  The  remainder  of  the 
wheel  only  embodies  modes  of  dividing  out,  previously 
explained,  so  we  just  jot  them  down  as  above  from  the 
drawing  without  comment — namely,  the  boss,  c,  the  flat 
arms,  d,  and  the  vertical  arms,  c. 

The  total  number  of  cubic  inches  is  599.  Multiplying 
by  0.263,  we  have  157  Ib.  weight  of  metal,  or  1  cwt. 
45  Ib.  in  the  wheel. 

The  next  illustration  is  a  bend  pipe  (Fig.  283).  This 
is  wholly  circular.  In  thin  castings  of  this  type  it  is  not 
usual  to  take  the  mean  diameter  of  the  ring  or  rings  of 
metal  into  which  we  conveniently  divide  the  castings, 
but  to  subtract  the  area  of  the  internal  diameter  or  bore 
from  the  area  of  the  external  diameter,  as  follows : 

In  the  pipe  shown  in  the  figure  the  lengths  are  given, 
as  is  usual,  from  the  centres  of  the  straight  lengths, 
A  and  B,  to  the  faces  of  the  flanges,  D  and  E.  We  shall 
find  it  convenient  to  deduct  the  bend  portion  from  the 
straight  portion,  to  facilitate  calculation.  This  gives 
two  straight  portions,  A  equalling  3  ft.  6  in.  — 9  in.  in 
length,  and  B  equalling  1  ft.  1  in.  — 9  in.  in  length,  and 
we  set  these  down  accordingly: 

Cub.  in. 

A  =  l  tube  2  ft.  9  in.  long  x  4  in.  and  5  in.  dia.  .  =  234 

B  =  l  tube  4  in.  long  x  4  in.  and  5  in.  dia. .     .     .  =  28.4 
C  =  quarter  bend  56.5  in.  circ.  x  4  in.  and  5  in.  dia.  =     99 
D  and  jB  =  2  flanges  9-J  in.  dia.  x  1  ft.  thick - 

5  in.  hole  .  =  100.8 


462.2 

The  bend,  (7,  happens  to  be  a  quarter  of  a  circle,  with 
mean  radius,  r,  of  9  in.    So  we  say  9  in.  x  2  =  1  ft.  6  in. 


WEIGHTS  OF  CASTINGS  381 

mean  diameter  =  56 J  in.  circumference,  and  we  want 
one-fourth  of  that  circumference,  and  we  set  down  C 
accordingly  in  list.  Last,  we  have  two  flanges,  D  and  E, 
each  9|  in.  diameter  x  1  in.  thick.  From  these  we  have 
to  deduct  holes  5  in.  diameter,  equal  to  the  outside  dia- 
meter of  the  pipe,  because  we  took  the  total  lengths  of 
A  and  B  over  the  faces  of  the  flanges.  We  put  down  the 
flanges  in  the  list  and  begin  our  calculations. 

Taking  A  first,  we  obtain  the  area  of  5  in.;  subtract 
the  area  of  4  in.  from  it,  and  multiply  by  2  ft.  9  in.= 
33  in.  We  do  not  go  through  the  process  each  time  of 

-  3'-6' •  -1 


FIG.  283.— BEND  PIPE. 

squaring  the  diameter  and  multiplying  by  0.7854,  but 
go  to  a  table  of  diameters  and  areas.  The  result  is,  area 
of  5  in.  =  19.6  in.;  area  of  4  in.  =  12. 5  in.;  then  19.6  in. 
—  12.5  in.  =  7.1  in.  area  of  cross-section  of  pipe,  which 
x  33  in.  =  234  in.,  which  we  set  down  accordingly  in  the 
list  of  items.  Then  ring  J5,  will  also  equal  7.1  in.  area 
x4  in.  =  28. 4  in.  The  cross-section  of  the  bend,  C,  is 
also  7.1  in.  The  mean  length  of  the  bend  is  56.5  in.-r-4 
=  14  in.,  and  7.1  in.  x  14  in.  =  99  in.  The  area  of  a 
single  flange  is  the  area  of  9.5  in.  — the  area  of  5  in. 
=  70  in.  — 19.6  in.  =  50.4  in.  There  are  two  flanges  = 
100.8  in. 

The  total   sectional  contents  of  the  pipe  is  462  in. 
Multiplying  by  263  =  121  lb.,  or  1  cwt.  9  Ib.  in  the  pipe. 


382  PRACTICAL  IRON  FOUNDING 

Another  way  to  run  through  the  weight  of  plain  pipes, 
and  any  plain  cylindrical  work,  is  to  make  use  of  a  table 
of  weights  of  pipes  or  columns  per  foot  run.  In  most 
engineers'  books  of  reference  these  tables  are  given  for 
cast-iron  cylinders  1  ft.  long,  of  diameters  ranging  from 
2  in.  or  3  in.  to  24  in.,  and  in  thicknesses  ranging  from 
about  J-  in.  to  1  in.  These  tables  cover  the  range  of  all 
ordinary  pipe  and  column  dimensions,  and  therefore  save 
some  little  time  in  subtracting  areas.  Again,  it  is  often  the 
practice  not  to  reckon  out  the  flanges  on  a  pipe  as  flanges, 
but  to  estimate  two  flanges  as  equal  to  1  ft.  in  length  of 
the  pipe,  which  in  standard  pipes  is  not  far  out. 

When  getting  out  approximate  estimates  by  direct  cal- 
culation there  is  a  good  deal  of  mental  work  done  which 
is  not  put  down  in  figures.  Thus  in  running  through  an 
intricate  piece  of  work  certain  allowances  or  set-offs  are 
made.  Certain  holes  will  be  set  off  against  certain  lugs, 
brackets,  corners,  angles,  and  so  forth,  when  one  appears 
to  about  counterbalance  the  other,  so  that  one  would  not 
be  set  down  at  all  in  the  calculations,  but  allowances 
would  be  mentally  made  for  it. 

Measurements  of  areas  and  of  volumes  have  to  be 
taken  with  great  expedition,  because  the  element  of 
time  presses.  Generally  all  rules  of  mensuration  which 
involve  much  calculation  are  passed  by,  and  figures  are 
averaged  into  rectangles,  triangles,  and  circles,  or  parts 
of  circles.  For  the  areas  in  the  first  case  two  dimensions 
only  have  to  be  multiplied  together.  In  the  second  the 
base  and  height,  and  half  the  product  taken.  In  the 
third,  a  table  would  be  consulted.  Flat  and  angular 
surfaces  are  either  brought  into  square  feet,  or  into  feet 
square,  and  of  a  definite  thickness.  Curved  surfaces,  of 
whatever  curve,  are  either  brought  into  flat  surfaces  of 


WEIGHTS  OF  CASTINGS  383 

square  feet,  or  feet  square,  or  into  annular  rings.  In 
either  of  these  forms  the  weights  are  easily  obtainable 
direct  from  tables. 

Not  only  are  tables  designed  for  use  with  a  given  metal 
employed,  but  tables  are  also  utilized  for  metals  other 
than  those  for  which  they  are  designed.  Thus  it  is  very 
easy  and  convenient  to  use  tables  of  weights  of  wrought 
iron  for  cast  iron  and  brass.  Tables  are  given  for  the 
weight  of  a  superficial  foot  of  various  thicknesses,  and 
of  the  weight  of  a  foot  run  of  bar  iron  of  various  thick- 
nesses and  widths,  and  these  can  be  utilized  for  any 
other  metal  by  the  employment  of  a  suitable  multiplier, 
often  saving  the  trouble  of  some  considerable  calculation 
when  a  table  of  similar  sections  is  not  available  for  the 
metal  or  alloy  required.  Thus  the  multiplier  0.9538 
converts  the  weight  of  bar  iron  into  that  of  cast  iron, 
0.929  steel  into  cast  iron,  1.15  bar  iron  into  gun  metal 
or  copper.  Not  that  any  single  calculation  in  itself 
amounts  to  much ;  but  when  hundreds  of  separate  cal- 
culations are  in  question,  a  trifle  of  time  saved  on  each 
makes  a  lot  of  difference  in  the  sum  total.  These  tables 
are  given  in  the  Appendix. 

Even  in  calculations  for  bringing  cubic  inches  into 
pounds,  many  do  not  use  the  multiplier  0.263  given  for 
cast  iron.  It  is  more  accurate  than  any  other.  But  for 
very  rough  estimating  some  simply  divide  cubic  inches 
by  4.  This,  however,  would  make  a  good  deal  of  differ- 
ence in  a  big  casting.  But  a  very  fair  approximation  is 
obtained  by  dividing  inches  by  4,  and  the  quotient  by  20, 
and  adding  the  two. 


APPENDIX 

TABLE  I 

Sand  Mixtures 

THESE  mixtures,  as  stated  in  Chapter  II,  p.  12,  are  given 
as  typical  and  illustrative  only  of  the  manner  in  which 
moulding  materials  are  prepared  to  suit  the  ever-varying 
requirements  of  the  foundry.  Only  from  this  point  of 
view  are  they  to  be  regarded  as  of  value. 

Two  mixtures  of  strong  sand  from  the  Manchester  dis- 
trict are : — 

(1)  2  barrows  of  red  sand. 
2       ,,  road  „ 

2  riddles  of  horse-manure. 
5  buckets  of  coal-dust. 

(2)  2  barrows  of  red  sand. 

4  ,,  ground  road  sand. 

5  sieves  of  coal-dust. 

1      ,,          black  sand. 

1  ,,          loam. 

Jobbing  or  common  sand:— 

4  barrows  of  red  sand. 

2  ,,  ground  road  sand. 
2      ,,  black  sand. 

6  sieves  of  coal-dust. 

c  c 


386  PRACTICAL  IRON  FOUNDING 

For  small  work: — 

3  riddles  of  red  sand. 

3      ,,  road  „ 

3      ,,  fine  yellow  sand. 

3  buckets  of  fine  coal-dust. 

For  fine  wheels:— 

3  riddles  of  red  sand. 

3      ,,  fine  yellow  sand. 

2  buckets  of  fine  coal-dust. 

In  the  West  of  England.    Strong  sand:— 
2  barrows  of  Seend  sand. 

1  ,,  Devizes  sand. 

2  ,,  loam. 

5  buckets  of  coal-dust. 

2  sieves  of  horse-manure. 

Sand  for  light  work:— 

5  barrows  of  black  sand. 
5      ,,  Seend    ,, 

3  buckets  of  coal-dust. 

Loam: — 

1  barrow  of  black  sand. 
H     i>  Seend    „ 

^     „  Devizes  sand. 

18  shovels  of  manure. 

The  above  mixture  with  half  the  amount  of  dung 
makes  a  good  core  sand. 

The  core  sand  used  at  Banbury  is  composed  of  equal 
parts  of  burnt  sand  and  a  porous  red  sand  obtained  in 
the  vicinity  of  Birmingham.  The  dry  sand  is  composed 
of  the  core  sand  ground  in  a  mill  and  thickened  with 
clay-wash.  The  red  sand  is  largely  used  in  Birmingham 


APPENDIX  387 

and  Manchester,  and,  like  the  Worcester  sand,  which  it 
resembles,  is  very  free  and  open,  being  largely  self- 
venting. 

In  the  Bradford  district  (Yorkshire)  a  red  sand  from 
the  Doncaster  district  is  employed  for  general  jobbing- 
work;  it  is  fairly  open. 

"  Winmore,"  a  very  open  gritty  sand,  is  used  for 
strong  green  sand  moulds. 

A  yellow  sand  from  Kippax  is  used  for  cores  and  for 
dry  sand  work. 

For  loam:  Doncaster  or  Kippax  sand  is  ground  with 
clay-wash,  and  horse-dung  or  cow-hair  added. 

Mansfield  sand  (Nottinghamshire)  is  used  for  fine 
work;  it  is  a  close  sand.  This  is  also  used  in  the  Eastern 
Counties.  A  little  old  sand  is  mixed  with  the  above, 
according  to  the  class  of  work. 

The  following  are  from  foundries  in  Bradford  :— 

(1)  Ordinary  green  sand  is  composed  either  of  Ponte- 
fract,  Doncaster,  or  Snaith  sand,  mixed  with  50  per  cent, 
of  old  sand,  and  1  part  of  coal-dust  to  8  or  10  of  sand, 
according  to  weight  of  casting. 

(2)  Fine  green  sand  for  small  moulds  and  teeth  of 
wheels  is  composed  of  Mansfield  sand,  with  from  25  to 
50  per  cent,  of  old  sand,  and  1  part  of  coal-dust  to  15  of 
sand. 

(3)  For  cores :  Pontefract,  Doncaster,  and  Snaith  sands 
are  used,  provided  they  are  free  from  clay. 

(4)  For  large  cores:  dried  loam  pounded,  and  horse- 
dung  dried  and  sieved,  are  mixed  with  the  above  sands 
in  various  proportions. 

(5)  Dry  sand:    for  facing — dried  loam  pounded,  and 
brought  to  consistence  of  green  sand;  for  box  filling — 
old  and  new  sand  mixed,  and  weak  clay- wash  added. 


388  PRACTICAL  IRON  FOUNDING 

From  another  firm  I  have:— 

(1)  For  common  green  sand:  yellow  sand  from  Kippax, 
and  red  sand  from  Snaith  and  Doncaster,  each  mixed 
with  old  sand  in  different  proportions,  according  to  the 
quality  of  the  work. 

(2)  For  fine  wheels:  Mansfield  sand. 

(3)  Strong  sand  is  prepared  from  Buttershaw  sand 
mixed  with  old  sand,  and  coal-dust  in  varying  propor- 
tions. 

(4)  Cores:  red  sand,  or  yellow  sand,  mixed  with  a  little 
clay  and  old  sand. 

From  a  Leeds  firm  :— 

(1)  Common  green  sand:    two-thirds  of  old  sand  to 
one-third  of  new  yellow  sand;  coal-dust  to  suit  work. 

(2)  Strong  sand :  one-half  old  sand,  one-quarter  yellow, 
and  a  quarter  red;  coal-dust  in  varying  proportions. 

(3)  Core  sand:  two-thirds  yellow  sand,  and  one-third 
manure. 

In  the  London  district  Erith  sand  is  largely  used;  in 
Scotland,  Belfast  and  Falkirk  sands;  each  district  and 
each  shop  having  its  own  special  mixtures;  but  the  fore- 
going will  suffice  to  illustrate  the  method  of  mixing. 


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SECTION  OP  ROOTS'  BLOWER 


VERTICAL  SECTION. 
Dimension  lettering  of  Cupola  to  correspond  with  Table  on  p.  390. 


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F-KS 

00 

H:, 

Hd 

Q 

^      3 

HH 

^ 

CO 

uo 

a     a 

N 

vO 

«H 

r^N 

r°     ^ 

** 

H 

"* 

CO 

o       o 

O 

^ 

LO 

^ 

cr>       ^> 

N 

t    1 

« 

00 

M 

Hsi 
CO 

'b'1 

- 

" 

i    & 

« 

- 

O 

CO 

* 

$ 

• 

e 

'      c« 

bo  <A 

• 

c 

B 

C 

"8  ' 

*J 

• 

o 

•      S^5 

'£  ^ 

o,  • 

0 

3 

u,  3 

<u 

cr 

SIZE  OF  BLOWER  .  .  . 

Maximum  Number  of  Revol 

•  i 

VH 

(U          ^3 

i   o 

a    § 
I   1 

Approximate  maximum  m 
capacity  at  this  delivery, 
of  iron  per  hour  .  .  . 

Diameter  of  Delivery  Orifice 

Diameter  of  Driving  Pulleys 

Breadth  of  Driving  Pulleys  . 

Approximate  B.H.P.  at  full 
and  at  21  in.  W.G.  .  .  . 

Approx.  Weight,  unpacked 

W    = 
J     W 
PQ     ^ 

<     ^ 

Hco 
C/3 

W 


11 


SIN 

^OMO 


JsN 

II 


OOO 


co 


OOQO 


IQOOO 


OO 


OOOO 

O    O    O   L 

^Cl      O-I 


r 

OO 


M  r<  co  -t  m\o  r-x  rv.oo  co  O  O 


ihtf  1 

Is!  § 

<U  T3    ^  O 

:4|  :- 

^^         cj  _* 


o 

' 


. 

tJ3  S 


. 
885 


.5  s 


394 


PRACTICAL  IRON  FOUNDING 


TABLE  VI. 

SIZES,  WEIGHTS,  PROOF   STRAINS,  AND   WORKING 
LOADS   OF   SHORT   LINK  CRANE   CHAIN. 


Size  of  Chain. 

Approximate 
Weight  per 
Foot  inlbs. 

Proof  Strain 
in  Cwts. 

Working  Load 
in  Cwts. 

i  '33 

3675 

20*0 

1-91 

45-0 

24*0 

2'33 

65-5 

27-0 

3'25 

75*0 

44-0 

| 

3-66 

I02'0 

I 

5'33 

I47-0 

80-0 

| 

671 

200-0 

IIO'O 

I 

9'33 

268-0 

140-0- 

ll 

11-9 

334'o 

1  80*0 

'* 

I4-5 

408-0 

220'0 

TABLE  VII. 

SIZES,  WEIGHTS,  WORKING  LOADS,  AND  BREAKING 
STRENGTHS   OF   HEMP   ROPES. 


Circumference 
in  inches. 

Weight  per  Fathom 
in  Ibs. 

Safe  Working 
Loads  in  Cwts. 

Breaking 
Strain  in  Cwts. 

23 

2'O 

6 

40 

4*o 

12 

80 

4^ 

5-0 

IS 

120 

$i 

7-0 

24 

1  60 

6 

9-0 

30 

200 

64. 

lO'O 

36 

240 

7* 

I2'O 

42 

280 

7k 

I4-0 

48 

320 

8 

1  6*O 

54 

360 

9k 

22  "O 

78 

520 

10 

25-0 

84 

560 

APPENDIX 


395 


TABLE  Mil— continued. 

SIZES,  WEIGHTS,  WORKING  LOADS,  AND  BREAKING 
STRENGTHS  OF  ROUND  STEEL  WIRE  ROPES. 


Circumference 
in  inches. 

Weight  per 
Fathom  in  Ibs. 

Safe  Working 
Loads  in  cwts. 

Breaking 
Strain  in  cwts. 

I 

ro 

9 

60 

'* 

1-50 

15 

100 

if 

2'0 

21 

140 

i| 

2^0 

27 

180 

2 

3'5o 

33 

220 

2} 

40 

39 

260 

2f 

4-50 

45 

300 

2f 

5-0 

5i 

340 

2\ 

5*5° 

60 

400 

2| 

6-50 

72 

480 

3r 

8-50 

84 

560 

3f 

5-0 

90 

6co 

3f 

10-50 

100 

720 

3! 

I2'0 

H5 

840 

I4-0 

126 

960 

TABLE  VIII. 

AVERAGE   COMPOSITION   OF   PIG   IRON. 


Grey. 

Mottled. 

White. 

Tio 

I'QQ 

( 

Combined  Ccirbon 

J  *w 

O'Od 

278 

J2'42 

Silicon  ...         .        

2'l6 

O7I 

o"?6 

Sulphur     

O'll 

trace 

0*87 

o'6"? 

I'23 

ro8 

oxo 

Q4''i6 

Q^*2Q 

QT27 

396  PRACTICAL  IRON  FOUNDING 


TABLE  IX 
MENSURATION 

1. — AREAS 

1.  Itectangle  or  Parallelogram.   Multiply  the  length  by 
the  breadth. 

2.  Triangle.  Multiply  the  base  by  the  perpendicular 
height,  and  take  half  the  product. 

Or:  From  half  the  sum  of  the  three  sides  subtract 
each  side  separately,  multiply  the  half  sum  and  the  three 
remainders  together;  the  square  root  of  the  product  will 
be  the  area. 

3.  Trapezoid.     Multiply  half  the  sum  of  the  parallel 
sides  into  the  perpendicular  distance  between  them. 

4.  Quadrilateral.     Divide    the   quadrilateral  into  two 
triangles;    the  sum  of  the  areas  of  the  triangles  is  the 
area. 

5.  Irregular  Polygon.  Divide  the  Polygon  into  triangles, 
and  trapezoids  by  drawing  diagonals;  find  the  areas  of 
these  as  above  shown  for  the  area. 

6.  Regular  Polygon.  Multiply  the  length  of  a  side  by  the 
perpendicular  height  to  the  centre  and  by  the  number  of 
sides,  and  half  the  product  will  be  the  area. 

7.  Circle.     Multiply    the    square   of    the    radius   by 
3-14159. 

Or :  Multiply  the  square  of  the  diameter  by  '7854. 

8.  Circular  Ring.   Find  the  area  of  each  circle,  and 
subtract  the  area  of  the  inner  circle  from  the  area  of  the 
outer  circle. 


APPENDIX  397 

Or:  Multiply  the  sum  of  the  radii  by  their  difference, 
and  the  product  by  3*14159. 

9.  Sector  of  a  Circle.   As  360  is  to-  the  number  of  de- 
grees in  the  angle  of  the  sector,  so  is  the  area  of  the  circle 
to  the  area  of  the  sector. 

Or :  Multiply  half  the  length  of  the  arc  of  the  sector  by 
the  radius. 

10.  Segment  of  a  Circle.   Find  the  area  of  the  sector 
which  has  the  same  arc,  and  subtract  the  area  of  the 
triangle  formed  by  the  radial  sides  of  the  sector  and  the 
chord  of  the  arc;    the  difference,  or  the  sum  of  these 
areas,  will  be  the  area  of  the  segment,  according  as  it  is 
less,  or  greater  than  a  semicircle. 

11.  Cycloid.    Multiply  the  area  of  the  generating  circle 
by  three. 

12.  Parabola.    Multiply  the  base  by  the  height;  two- 
thirds  of  the  product  is  the  area. 

13.  Ellipse.   Multiply  the  product  of  the  two  axes  by 
•7854. 

NOTE. — The  area  of  an  ellipse  is  equal  to  the  area  of  a 
circle,  of  which  the  diameter  is  a  mean  proportional  be- 
tween the  two  axes. 


II. — VOLUMES 

14.  Parallelepiped,  Prism,  ox  Cylinder.  Multiply  together 
the  length,  the  breadth,  and  the  height,  and  the  product 
will  be  the  volume. 

Or:  Multiply  the  area  of  the  base  by  the  height,  and 
the  product  will  be  the  volume. 

15.  Pyramid  or  Cone.   Multiply  the  area  of  the  base  by 
the  height,  and  one-third  of  the  product  will  be  the 
volume. 


398  PRACTICAL  IRON  FOUNDING 

16.  Wedge.   To  twice  the  length  of  the  base  add  the 
length  of  the  edge ;  multiply  the  sum  by  the  breadth  of 
the  base,  and  by  the  height.    One-sixth  of  the  result  will 
be  the  volume. 

17.  Sphere.    Multiply  the  cube  of   the  diameter  by 
•5236. 

18.  Spherical   Shell    Subtract  the  cube  of  the  inner 
diameter  from  the  cube  of  the  outer  diameter,  and  multi- 
ply the  result  by  -5236. 

19.  Zone  of  Sphere.    To  three  times  the  sum  of  the 
squares  of  the  radii  of  the  ends  add  the  square  of  the 
height;  multiply  the  sum  by  the  height  and  by  '5236. 

20.  Segment  of  Sphere.    To  three  times  the  square  of 
the  radius  of  the  base  add  the  square  of  the  height; 
multiply  the  sum  by  the  height,  and  the  product  by 
•5236. 


APPENDIX 


399 


TABLE  X. 

WEIGHT   OF  TWELVE   INCHES   SQUARE   OF 
VARIOUS    METALS. 


Thick  Wrought 
ness,  i     Iron. 

Cast 
Iron. 

Steel. 

Gun 

Metal. 

Brass. 

Copper. 

Tin.     '    Zinc. 

Lead. 

inch.  1      Ibs. 

Ibs. 

Ibs. 

Ibs. 

Ibs. 

Ibs. 

Ibs.           Ibs. 

Ibs. 

i 

2-50 

2'34 

2-56 

275 

2*69 

2*87 

2-37 

2-25 

3*68 

jj 

5' 

4*69 

5*12 

5'5 

5'38 

575 

475 

4'5 

7-37 

7 

7-50 

7'o.j 

7-68 

8-25 

8*07 

8*62 

7-12 

675 

11*05 

IO" 

9-38 

10-25 

IT 

1075 

11-5 

9'5 

9' 

14-75 

1  6 

12-5 

1172 

12-81 

1375 

13-45 

1437 

11-87 

11-25 

18-42 

f        I5' 

14*06 

15-36 

16-50 

16*14 

17-24 

14-24 

13-50 

22*10 

A    '7-5 

16*41 

1  7  "93 

19-25 

18-82 

20'  1  2 

16-17 

1575 

25-80 

A        20- 

1875 

20-5 

22' 

21*5 

23" 

19- 

18- 

29-5 

T9?      22"5 

2TIO 

23-06 

2475 

24-20 

25^7 

21-37 

20*25 

33-I7 

|-        25- 

23'44 

25-62 

27*50 

26*90 

28-74 

^374 

22*50 

36-84 

li      27-5 

2579 

28*18 

30*25 

29-58 

31-62 

26-12    12475 

40-54 

1 

30* 

28*12 

30-72 

33*00 

32*28 

34-48 

28-48     |27- 

44-20 

¥  ;^5 

30-48 
32-82 

33-28 
35-86 

3575 
38-50 

57-64 

40-24 

30*87     (29-25 

32-34   l3i'5 

47-92 
5^6 

A  37-5 

35-I6 

38-43 

41-25 

40-32 

43-12 

35'6i    J3375 

55^6 

i 

40- 

37'5 

41' 

44' 

43" 

46- 

38-       (36* 

59' 

400 


PRACTICAL  IRON  FOUNDING 


TABLE  XL 

WEIGHT   OF   CAST   IRON   CYLINDERS 
ONE   FOOT   LONG. 


External 
Diameter. 

Thickness  in  Inches. 

i 

1 

* 

1 

I 

1 

I 

inches. 

Ibs. 

Ibs. 

Ibs. 

Ibs. 

Ibs 

Ibs. 

Ibs. 

3 

6*75 

9-65 

1  2'3 

I4'6 

16-6 

18-3 

19*6 

31 

7-98 

11-5 

147 

17-6 

20-3 

22-6 

24-5 

4 

9-20 

i.3*3 

17-2 

20-7 

2AaO 

26*9 

29-5 

41 

1  0-4 

15-2 

19*6 

23*8 

277 

31-1 

34*4 

5 

11-7 

17-0 

22'I 

26*9 

31*5 

35*4 

39*3 

54 

12-9 

18-9 

24-5 

29'9 

35*2 

39*7 

44*2 

6 

14-1 

20-7 

27-0 

33*o 

44*o 

49-1 

6| 

15-3 

22-5 

29-5 

36*1 

42*6 

48*3 

54-0 

7 

16-6 

24-4 

31*9 

39*i 

46-4 

52-6 

58-9 

71 

17-8 

26-2 

34*4 

42-2 

50-1 

56-9 

63-8 

8 

19-0 

28-1 

36-8 

45*3 

53*8 

61-2 

68-7 

84 

9 

20-3 
21-5 

29-9 

39*3 
41*7 

48*3 
5i*4 

I7'5 
6i'3 

65*5 

69-8 

73*6 
78-5 

91 

227 

33*6 

44*2 

54*5 

65-0 

74-1 

83*5 

10 

23-9 

35'4 

46-6 

57*5 

68-7 

78-4 

88-4 

ii 

26*4 

39*  i 

51*5 

63*7 

76*0 

87-0 

98-2 

12 

28-8 

42-8 

56-5 

69-8 

83*4 

95-6 

io8'o 

13 

3T*3 

46-5 

61-4 

75*9 

90-7 

104-2 

117-8 

14 

33*8 

50-2 

66-3 

82-1 

98-0 

112*8 

127-6 

15 

36*2 

53*8 

71-2 

88-2 

105-4 

121-3 

137*4 

16 

387 

57*5 

76-1 

94*3 

1127 

129-9 

147*3 

17 

41-1 

61-2 

8ro 

100*5 

I20'0 

138-5 

157-1 

18 

43*6 

64-9 

85*9 

1  06  '6 

I27-4 

147-1 

1  66  -9 

19 

46-0 

68-6 

90-8 

1  12-8 

1347 

1557 

1767 

20 

48-5 

72-3 

957 

118-9 

I42-0 

164*3 

186-5 

21 

50-9 

75*9 

ico-6 

125-0 

I49-4 

172-9 

196-4 

22 

53*4 

79-6 

105-5 

131-2 

1567 

181-5 

206'2 

23 

55*8 

83*3 

110-5 

137*3 

164-0 

190-1 

215*0 

24 

58-3 

87-0 

115-4 

143*4 

I7I-4 

1987 

225-8 

APPENDIX 


401 


TABLE  XI— continued. 


External 
Diameter. 

Thickness  in  Inches. 

i 

I 

1 

1 

I 

1 

. 

inches. 

Ibs. 

Ibs. 

Ibs. 

Ibs. 

Ibs. 

Ibs 

Ibs. 

25 

60'8 

90-7 

I20-3 

I49-6 

1787 

207-2 

235-6 

26 

63-2 

94-3 

I25-2 

1557 

186-1 

215-8 

245-4 

27 

657 

98-0 

130'! 

i6r8 

193-4 

224-4 

2553 

28 

68-1 

1017 

I35-0 

168-0 

200-7 

233'0 

265-1 

29 

70*6 

105-4 

139*9 

174-1 

208-1 

24I-6 

274-9 

3° 

73*o 

109-1 

144-8 

180-2 

215-4 

250*2 

2847 

3i 

75'5 

112-8 

1497 

186-4 

2227 

258-8 

294-5 

32 

77'9 

116-4 

I54-6 

192-5 

230-1 

267-4 

304-3 

33 

80-4 

1  20'  I 

I59'5 

1987 

237-5 

276-0 

3H-2 

34 

82-8 

I23-8 

164-5 

204-8 

244-8 

284-6 

324-0 

35 

85-3 

127-5 

169-4 

210-9 

252-2 

293T 

333-8 

36 

87-8 

I3r2 

174*3 

217-1 

259-5 

3017 

343'6 

38 

927 

I38-5 

184*1 

229-3 

274-3 

3I8-9 

363-2 

40 

97-6 

1  45  '9 

193*9 

241*6 

289-0 

336-I 

382-9 

42 

I02'5 

I53'3 

2037 

253'9 

303-7 

353'3 

402-5 

45 

109-8 

164-3 

218-5 

272-3 

325-8 

379-1 

432-0 

48 

117-2 

175*4 

233-2 

290-7 

347-9 

404*8 

461-4 

5' 

124-6 

186-4 

247-9 

309-1 

370-0 

430-6 

490-9 

54 

131-9 

197-5 

262-6 

327-5 

392-1 

456-4 

520-3 

57 

I39"3 

208-5 

277-4 

345-9 

414-2 

482'  I 

549-8 

60 

146-6 

219*6     |  292*1 

364-3 

436-3 

507-9 

579'3 

D  D 


402 


PRACTICAL  IRON  FOUNDING 


TABLE  XII. 
COMPARATIVE  WEIGHTS   OF  DIFFERENT  BODIES. 


Cast  Iron  =  i 

Bar  Iron 

=i 

Steel  si 

Bar  Iron      =1-0484 

Cast  iron 

=   -9538 

Cast  iron        = 

•929 

Steel             =  i  -0766 

Steel 

=  1*0269 

Bar  iron         = 

•97378 

Brass            =1-153 

Brass 

=  1*1 

Brass              = 

1*07 

Copper         =1*2137 

Copper 

=  1-15163 

Copper 

1*1236 

Gun  metal  =1-208 

Gun  metal 

=  1*15094 

Gun  metal     = 

1*12132 

Lead            =1-5645 

Lead 

=  1*5 

Lead               — 

r4532 

Brass  =  i 

Copper  =  i 

Gun  Metal  =  i 

Cast  iron      =   '867 
Bar  iron       =   -909 
Steel             =   -9336 
Copper         =  i  -05 
Gun  metal  =  i  "046 
Lead            =  i'357 

Cast  iron         =   "83 
Bar  iron           =   "8666 
Steel                 =  -89 
Brass                =   -95 
Gun  metal       =  "9994 
Lead                 =1-293 

Cast  iron      =  '82888 
Bar  iron       =    '86874 
Steel             =  '891735 
Brass            =   "95583 
Copper         =  I  '00045 
Lead            =  i  -29246 

Lead=i 


Yellow  Pine  =  i 


Cast  iron 

=  •64 

Cast  iron 

=  16*0 

Bar  iron 

=  •67 

Steel 

=  17*0 

Steel 

=  •688 

Brass 

=  18-8 

Brass 

=  737 

Gun  metal 

=  19*0 

Copper 

=  774 

Copper 

=  I9'3 

Gun  metal 

=  7736 

Lead 

=  24*0 

APPENDIX 


403 


TABLE  XIII. 
WEIGHT  OF   CAST   IRON   BALLS. 


Diameter 
in  inches 

Weight 
in  Ibs. 

Diameter 
in  inches. 

Weight 
in  Ibs. 

Diameter 
in  inches. 

Weight 
in  Ibs. 

2 

no 

6 

2972 

10 

I377I 

2T 

1-57 

6i 

33-62 

I0i 

I48-28 

2i 

2-15 

61 

37-80 

lOl- 

I59-40 

2| 

2-86 

6J 

4235 

io| 

I7I-05 

3 

372 

7 

47-21 

II 

183-29 

3i 

4-71  - 

/  ~Z 

52-47 

III 

196*10 

31 

5-80 

7l 

58-06 

Hi 

209-43 

3i 

7-26 

64-09 

1  !l 

223-40 

4 

8-8  1 

s4" 

70-49 

12 

237^4 

4£ 

10-57 

8i 

77-32 

I2i 

253-I3 

41 

12-55 

8i 

84-56 

I21 

268-97 

4f 

14-76 

8| 

92-24 

* 

28537 

5 

17-12 

9f 

100-39 

I3r 

302-41 

5? 

19-93 

108-98 

320-80 

51 

22-91 

91 

1  1  8'o6 

13! 

338*81 

si 

26-18 

V 

9i 

127-63 

J3| 

3  57  '93 

404 


PRACTICAL  IRON  FOUNDING 


TABLE  XIV. 

DECIMAL  EQUIVALENTS  TO  FRACTIONAL   PARTS 
OF  LINEAL  MEASURES. 


One  inch  the  integer  or  whole  number. 


•96875 

?&A 

'625 

•28125 

t&A 

'9375 

f  &  "*? 

'59375 

'&     3 

•25 

i 

4. 

•90625 

•5625 

I&S 

•21875 

o    f|¥ 

•875 

°    i 

O 

f  &  ^ 

•1875 

'84375 

1    1  &  Y 

'5 

75 

•15625 

TJ    3-  &  yf 

•8i25 

•46875 

CT- 

1  &   ?  _ 

I  -125 

r  i 

•78125 
75 

f  !*$ 

ci       T 

'4375 
•40625 

0 
ctf 

8    &  Y% 

f  &  Ti 

:  '09375 
/0625 

a  ¥ 

•71875 

—  &  •f'— 

'375 

Sf 

•03125 

i 

'6875 

1  &  y^ 

'34375 

1  1  ¥ 

1 

•65625 

8         Ti 

•3125 

TABLE  XV. 

DECIMAL  APPROXIMATIONS   FOR   FACILITATING 
CALCULATIONS   IN    MENSURATION. 

Square  inches  multiplied  by  '007       =   Square  feet. 


Cubic  inches 


Avoirdupois  Ibs. 


„    "00058  =   Cubic  feet. 

„    '263       =   Lbs.  Avs.  of  Cast  iron. 

„  Wrought  iron. 

„  Steel. 

„  Copper. 

„  Brass. 

„  Zinc. 

„  Lead. 


•281 
•283 
•3225 

•3037 

•26 

•4103 

•2636 

•4908 

•009 


=   Cwts. 


„  Tin. 

„  Mercury. 


•00045  =  Tons. 


INDEX 


ALUMINIUM,  35. 
Analysis  of  sands,  15-17. 
Angles  in  castings,  132. 
Anvil  block,  163. 
Appendix : 

Tables  I.  Sand  mixtures,  385. 
„     II,  III.  Particulars,  "Ra- 
pid "  cupolas,  389, 
390. 
,,     IV.  Particulars,      Koot's 

blowers,  392. 
V.  Sturtevant  fans,  393. 
,,     VI.  Crane  chains,  394. 
,,  VII.  Ropes,  various,   394, 

395. 
,,VIII.  Composition    of    pig 

iron,  395. 
,,     IX.  Mensuration,  396- 

398. 
,,      X.  Weights    of    various 

metals,  399. 

,,     XI.  Weights  of  cast  iron 

cylinders,  400,401. 

,,  XII.  Comparative  weights, 

402. 
,,XIII.  Weights,    cast    iwfa 

balls,  403. 
„  XIV.  Decimal  equivalents, 

404. 

,,    XV.  Decimal   approxima- 
tions, 404. 

Back  plates,  101. 
Bar  tester,  38. 
Bars,  94,  95. 


Bead  tools,  112. 

Bedding-in,  138. 

Bend  pipe,  259. 

Bessemer  converters,  91. 

Black  sand,  7. 

Black  wash,  13. 

Blackening,  13. 

Blacking,  13. 

Blacking,  wet,  13. 

Blast,  60. 

Blowers,  62-64. 

Blow  holes,  124. 

Bogie  tracks,  75. 

Bottom  boards,  263. 

Box  filling,  7. 

Bricking  up,  238. 

Bricks,  238. 

Bricks,  loam,  120. 

Broken  castings,  moulding  from, 

364-371. 
Buckley    and      Taylor's     wheel 

moulding  machine,  329-334. 
Burning  on,  371. 
Burnt  iron,  31. 
Burnt  sand,  12. 

Calipers,  238. 
Casting  bosses,  177. 
Casting  ladles,  65-70. 
Casting  on  end,  188. 
Casting  pits,  76. 
Castings,  curving  of,  114. 
Castings,  shrinkage  of,  113. 
Castings,  weight  of,  372-383. 
Chains,  394. 


405 


406 


INDEX 


Chaplets,  225. 

Charcoal,  13. 

Charging  of  cupolas,  50,  51. 

Checks,  246. 

Chilling,  44,  45. 

Cinder  bed,  144. 

Cinders,  144,  239. 

Clay  plugs,  162. 

Clean  castings,  13. 

Cleaner,  110. 

Coal  dust,  9. 

Coal,  grinding  of,  26. 

Coal  mill,  26. 

Coke,  53. 

Coke  bed,  164,  228. 

Cold  shuts,  128. 

Collapsible  core  bars,  84. 

Compressed  air,  87. 

Converters,  91. 

Copes,  93,  94. 

Core  bars,  218. 

Core  bars,  collapsible,  220. 

Core  carriage,  93. 

Core  grids,  217. 

Core  irons,  218. 

Core  making,  192-197,  232. 

Core  making  machines,  319. 

Core  ovens,  74. 

Core  plates,  219. 

Core  prints,  223,  228. 

Core  ropes,  220. 

Core  sand,  11. 

Core  stoves,  74,  228. 

Core  strings,  221. 

Core  vents,  221,  227. 

Cores,  215-233. 

Cores,  drying  of,  11,  74. 

Cores,  green  sand,  11. 

Cores,  grids  for,  217. 

Crane  chains,  394. 

Cranes,  81. 

Crystallization,  116. 

Cupola  blast,  60. 

Cupola,  charging  of,  53. 


Cupola,  chemical  actions,  54. 
Cupola,  drop  bottom,  59. 
Cupola  furnaces,  46-60,  73. 
Cupola,  "  Rapid,"  55,  56. 
Cupola  tuyeres,  49,  57,  58. 
Curving  of  castings,  114. 
Cylinder  moulding,  187,  197-209. 

Decimal  approximations,  404. 

Decimal  equivalents,  404. 

Delivery  of  patterns,  148,  272. 

Drags,  93,  95. 

Drawing  of  castings,  128-132. 

Drawing  of  patterns,  363-364. 

Drop  bottom,  59. 

Dry  sand,  10. 

Dry  sand,  moulding  in,  185. 

Drying,  10. 

Drying  stoves,  74. 

Electric  power,  86. 

Facing  sand,  8. 
Fans,  61,  62,  64. 
Feeder  head,  160. 
Feeder  rods,  160. 
Feeding,  159. 
Fillets,  133. 
Finning,  185. 
Flasks,  93-108. 
Flasks,  forms  of,  101. 
Flow  off  gates,  161. 
Forms  of  flasks,  101. 
Forms  of  prints,  86. 
Foundries,  71-92. 
Foundry  cranes,  81. 
Foundry  pit,  76,  77. 
Fracture  of  castings,  115. 

Gear  moulding-bevels,  344. 
Gear  moulding  machine,  328-334. 
Gear  moulding-spurs,  335. 
Geared  ladles,  67. 
Goodwin  and  How's  patent  ladle, 
70. 


INDEX 


407 


Green  sand,  6. 

Green  sand  cores,  11. 

Green  sand  moulding,  163-184. 

Gray  iron,  30. 

Grids,  217,  218,  342. 

Guide  irons,  258. 

Hard  ramming,  126,  127,  186. 

Hay  bands,  218. 

Head  metal,  209-214. 

Heating,  90. 

Hemp  ropes,  197. 

Hollows,  133. 

Honeycombing,  122. 

Horse  manure,  10. 

Hydraulic    moulding    machines, 

310-314,  317. 
Hydraulic  power,  88. 

Ingates,  154,  156,  158. 

Iron,  28-46. 

Iron  and  aluminium,  35,  36. 

Iron,  burnt,  31. 

Iron,  economical  melting  of,  59. 

Iron,  foreign  constituents  of,  35. 

Iron,  gray,  30. 

Iron,  mottled,  31. 

Iron,  pig,  29. 

Iron,  remelting,  34,  35. 

Iron,  testing  of,  36-44. 

Iron,  white,  30. 

Jar-ramming  moulding  machines, 

323-326. 

Joint  boards,  263. 
Joints,  98,  140,  163,  185,  190. 
Joints,  lapping,  133. 

Ladles,  65-70. 

Ladles,  geared,  67. 

Ladles,     Goodwin     and     How's 

patent,  70. 
Lapping  joints,  133. 
Liftering,  147. 
Lifters,  146. 


Loading,  100. 

Loam,  11. 

Loam  boards,  236,  248. 

Loam  bricks,  120,  242. 

Loam  cakes,  152.  159. 

Loam  mill,  19. 

Loam  moulding,  234-251. 

Loam  patterns,  252-262. 

Loam  plates,  236,  240,  244,  250, 

256. 
Loam  work,  234-251. 

Machine  moulded  gears,  329-346. 
Machine  moulding,  262-346. 
Machines,  81,  89. 
Machines  for  sand   preparation, 

19-27. 

Manganese,  35. 
Melting  ratio,  58,  59. 
Mending  up,  148. 
Mending  up  pieces,  149. 
Mensuration,  396. 
Middle  parts,  93,  96. 
Mixing  of  sand,  12,  18-27. 
Mottled  iron,  31. 
Mould  for  cylinder  cover,  156. 
Mould  for  anvil  block,  163. 
Mould  press,  279. 
Moulding  a  tuyere,  229. 
Moulding  boxes,  93-108. 
Moulding  by  machine,  262-346. 
Moulding  a  cross,  177. 
Moulding  cylinders,  187,  197-209. 
Moulding  in  dry  sand,  185. 
Moulding  in  green  sand,  163-184. 
Moulding  in  loam,  234-251. 
Moulding  in  open  sand,  137. 
Moulding  machines,  278,  283,  284, 

286,  294,  295,  297,  301,  302,  306, 

312,  313,  315,  316. 
Moulding,  plate,  264. 
Moulding  of  fly-wheel,  166. 
Moulding  of  sheave  wheel,  141, 

142. 


408 


INDEX 


Moulding  of   trolly   wheel,    140, 

264. 

Moulding,  principles  of,  1. 
Moulding  sand,  1,  2,  4-27. 
Moulding  a  soap  pan,  247. 
Moulds,  permanent,  45. 
Multiple  moulding,  315. 

Nailing,  147. 

Offices,  78. 
Old  sand,  7. 
Open  sand,  137. 

Parting  sand,  12. 
Patterns,  delivery  of,  148. 
Pattern     of    fly-wheel    segment, 

168,  170. 

Patterns,  2,  3,  348. 
Patterns  in  loam,  252. 
Permanent  moulds,  45. 
Phosphorus,  35. 
Pig  iron,  29. 
Pits,  76. 

Plate  moulding,  264. 
Plated  patterns,  265-269. 
Plugs,  162,  166. 
Plumbago,  13. 
Pocket  prints,  224. 
Portable  moulding  machine,  295. 
Pouring,  150. 
Pouring  basins,  152. 
Pouring  moulds,  150. 
Power,  83. 

Pressure,  100,  134,  166. 
Prints,  forms  of,  223. 
Prints,  pocket,  224. 
Prods,  242. 
Pumping,  159. 

Rammers,  108,  109. 
Ramming,  269. 
Rapping,  148,  272,  273. 
Reverse  mould,  168,  343,  344. 
Riddles,  22,  23. 


|   Risers,  154,  161. 
Rockover     moulding     macnines, 

294. 

Rodding,  146. 

Root's  rotary  blower,  63,  392. 
Ropes,  hemp,  394. 
Ropes,  wire,  394,  395. 
Runner  spray,  157. 
Runner  stick,  157. 
Runners,  152,  158. 
Running,  152. 

Sand,  1,  2,  4-27. 

Sand,  black,  7. 

Sand,  burnt,  12. 

Sand,  chemistry  of,  14. 

Sand,  core,  11. 

Sand,  dry,  10. 

Sand,  facing,  8. 

Sand,  green,  6. 

Sand,  grinding,  19. 

Sand,  machines  for,  19. 

Sand,  mixing  of,  12,  18-27. 

Sand,  parting.  12. 

Sand,  preparation  of,  18-27. 

Sand  sifters,  20-23. 

Scabbing,  126. 

Scrap,  29,  32,  34. 

Shops,  71-92. 

Shrinkage,  41-43. 

Shrinkage  of  castings,  113. 

Sieves,  22,  23. 

Silicon,  35,  42,  43. 

Skimmer,  70. 

Skimming  chamber,  154. 

Skin  drying,  10. 

Slagging,  51. 

Sleekers,  112. 

Sleeking,  127. 

Snap  flasks,  103-108. 

Soap  pan,  247. 

Socket  bend,  259. 

Soft  ramming,  127. 

Specialization,  326,  327. 


INDEX 


409 


Spray  of  runners,  157. 

Sprigging,  147. 

Sprigs,  147. 

Staking,  98. 

Stays,  94-96. 

Steam  power,  85. 

Stewart's  patent  "Rapid "  cupola, 

55,  390. 

Stopping  off,  361-363. 
Stopping  over,  224. 
Stops,  225. 
Stoves,  74,  228. 
Strap,  236. 

Strickles,  258,  350,  351,  353. 
Stricklmg,  258-261,  350,  353. 
Striking  bar,  235. 
Striking    boards,   236,    335,  338- 

340,  343-345,  359. 
Stripping  plates,  273,  292,  306. 
Strong  sand,  8. 
Sulphur,  35. 
Swab,  148. 
Swabbing,  148. 
Sweeping  up,  166. 
Swivels,  .101. 

Taper,  3. 

Tapping  of  metal,  50,  51. 

Tar,  252. 

Test  bars,  37,  43. 

Testing  machine,  38. 

Thicknessing,  258,  260,  261. 

Three  parted  mould,  142. 

Tools,  108-112 

Top  parts,  93. 


Tacks,  75. 

Trowels,  110. 

Turn  over  boards,  263. 

Turning  over,  139,  143,  271. 

Tuyere  moulding,  229. 


Universal 
297. 


moulding     machine, 


Vent  pipes,  144,  164,  179,  228. 
Vent  wires,  109. 
Ventilation,  90. 
Venting,  144. 
Venting  in  loam,  103. 
Vents,  144. 

Vents,  choking  of,  144. 
Vents,  securing  of,  227. 
Vibrator    frame    moulding     ma- 
chine, 302. 

Weighting,  100. 
Weights,  comparative,  402. 
Weights  of  castings,  372-383. 
Weights  of  cast  iron  balls,  403. 
Weights  of  cast   iron  cylinders, 

400. 

Weights  of  metals,  399. 
Wet  blacking,  13. 
Wheel  moulding  machine,   329- 

334. 

Wheel  teeth,  335,  337. 
Wheels,   moulding  of,  329,   361- 

364. 

White  iron,  30. 
Wire  ropes,  395. 


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